Answer:
Slope: 3
Y intercept: y = 75
Step-by-step explanation:
The slope of a linear function is the coefficient in front of x. In this case, 3 is being multiplied by x, indicating the slope is 3.
The y-intercept is the y value where the graph of the function crosses the y-axis. In other words, it's the y value when x = 0. To find the y-intercept, simply substitute 0 for x:
[tex]y = 3(0) + 75 \\ y = 75[/tex]
We find that the y-intercept is y = 75.
In the linear function y=3x+75, the slope 3 represents the rate of cost per mile to tow a car ($3/mile), and the y-intercept 75 is the basic fee for the towing service. So, the total cost is a fixed fee of $75 plus $3 per mile towed.
Explanation:In the linear function y = 3x + 75, the slope, represented by '3', is the cost in dollars per mile to tow a car. This means for each mile the car is towed, the cost increases by $3.
The y-intercept, represented by '75', is the basic fee for the service, or the cost in dollars that one must pay even if the car isn't towed any miles.
So, to interpret the equation function: the total cost (y) of having a car towed is composed of a fixed fee of $75 plus an additional $3 for each mile (x) the car is towed.
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Provide in simplest form
12% of 40
a community program choose 16 fifth grade students every year and provide each of them with the same amount of money to attend music or art camp last year the program awarded a total of 8,400 to the students how much
Answer: 525
Step-by-step explanation: As I read the question I’m getting the idea of division. The community program chooses 16 students every year. The 8,400 dollars from last year was the amount of money the students receive all together. Therefore 8,400 divided by 16 is 525
Final answer:
Each of the 16 fifth grade students received $525 from the community program to attend music or art camp, calculated by dividing the total funds of $8,400 by 16 students.
Explanation:
The question asked is about calculating the amount of money awarded to each of the 16 fifth grade students by a community program for attending music or art camp. Since the program awarded a total of $8,400 last year and 16 students were chosen, we need to perform a simple division to find out how much money each student received. To do this, we divide the total amount of money ($8,400) by the number of students (16).
Step-by-step Calculation:
Divide the total amount of money by the number of students: $8,400 \/ 16.
Calculate the result to determine the amount per student.
Therefore, each student received $525 to attend the music or art camp.
At the local racetrack, the favorite in a race has odds 3:2 of losing. What is the probability that the favorite wins the race?
a. 0.2
b. 0.67
c. 0.6
d. 0.4
Answer:
0.40
Step-by-step explanation:
Given that at the local racetrack, the favorite in a race has odds 3:2 of losing
Here instead of probability odds are given.
Odds of losing = 3/2
Hence Probability of losing = [tex]\frac{3}{3+2} \\=\frac{3}{5} \\=0.6[/tex]
Probability that the favourite wins the race will be the probability for the event which is complement of losing the game.
Hence
Probability that the favourite wins the race will be the probability
= 1- 0.6
=0.40
Probability that favorite wins the race is 0.6
Given that;Favorite in a race has odds = 3:2
Find:Probability that favorite wins the race
Computation:Probability that favorite wins the race = 3 / [3 + 2]
Probability that favorite wins the race = 3 / 5
Probability that favorite wins the race = 0.6
Option "C" is the correct answer to the following question.
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Construct the indicated confidence interval for the difference between the two population means. Assume that the two samples are independent simple random samples selected from normally distributed populations. Also assume that the population standard deviations are equal (σ1= 2 ), so that the standard error of the difference between means is obtained by pooling the sample variances. A paint manufacturer wanted to compare the drying times of two different types of paint. Independent simple random samples of 11 cans of type A and 9 cans of type B were selected and applied to similar surfaces. The drying times, in hours, were recorded. The summary statistics are as follows.Type A: X1= 71.5hr, S1=3.4 hr N1=11Type B: X2=68.5 hr, S2= 3.6 hr, N2= 9Construct a 99% confidence interval for μ1-μ2 , the difference between the mean drying time for paint type A and the mean drying time for paint type B.
Answer:
The indicated confidence interval for the difference between the two population means is (-1.5159, 7.5159)
Step-by-step explanation:
Let the drying times of type A be the first population and the drying times of type B be the second population. Then
We have small sample sizes [tex]n_{1} = 11[/tex] and [tex]n_{2} = 9[/tex], besides [tex]\bar{x}_{1} = 71.5[/tex], [tex]s_{1} = 3.4[/tex] , [tex]\bar{x}_{2} = 68.5[/tex] and [tex]s_{2} = 3.6[/tex]. Therefore, the pooled
estimate is given by
[tex]s_{p}^{2} = \frac{(n_{1}-1)s_{1}^{2}+(n_{2}-1)s_{2}^{2}}{n_{1}+n_{2}-2} = \frac{(11-1)(3.4)^{2}+(9-1)(3.6)^{2}}{11+9-2} = 12.1822[/tex]
The 99% confidence interval for the true mean difference between the mean drying time of type A and the mean drying time of type B is given by
[tex](\bar{x}_{1}-\bar{x}_{2})\pm t_{0.01/2}s_{p}\sqrt{\frac{1}{11}+\frac{1}{9}}[/tex], i.e.,
[tex](71.5-68.5)\pm t_{0.005}(3.4903)\sqrt{\frac{1}{11}+\frac{1}{9}}[/tex]
where [tex]t_{0.005}[/tex] is the 0.5th quantile of the t distribution with (11+9-2) = 18 degrees of freedom. So
[tex]3\pm(-2.8784)(3.4903)(0.4495)[/tex], i.e.,
the indicated confidence interval for the difference between the two population means is (-1.5159, 7.5159)
For results based on a small random sample from a bell-shaped distribution, the distribution of the sample mean is
A. approximately a normal distribution.
B. not a bell-shaped distribution.
C. a uniform distribution.
D. approximately a standard normal (z-score) distribution
Answer:
A. approximately a normal distribution.
Step-by-step explanation:
There may be a few differences, but the sampling distribution of the sample mean is still approximately normal.
So the correct answer is:
A. approximately a normal distribution.
Answer:
Correct answer is (A) {Normal distribution}
Step-by-step explanation:
sampling distribution of the sample mean is still approximately normal.
Assume that it takes a college student an average of 5 minutes to find a parking spot in the main parking lot. Assume also that this time is normally distributed with a standard deviation of 2 minutes. Find the probability that a randomly selected college student will take between 2 and 6 minutes to find a parking spot in the main parking lot.
Answer:
0.624 is the probability that a randomly selected college student will take between 2 and 6 minutes to find a parking spot in the main parking lot.
Step-by-step explanation:
We are given the following information in the question:
Mean, μ = 5 minutes
Standard Deviation, σ = 2 minutes
We are given that the distribution of time is a bell shaped distribution that is a normal distribution.
Formula:
[tex]z_{score} = \displaystyle\frac{x-\mu}{\sigma}[/tex]
P(student will take between 2 and 6 minutes )
[tex]P(2 \leq x \leq 6) = P(\displaystyle\frac{2 - 5}{2} \leq z \leq \displaystyle\frac{6-5}{2}) = P(-1.5 \leq z \leq 0.5)\\\\= P(z \leq 0.5) - P(z < -1.5)\\= 0.691 - 0.067 = 0.624 = 62.4\%[/tex]
[tex]P(2 \leq x \leq 6) = 62.4\%[/tex]
0.624 is the probability that a randomly selected college student will take between 2 and 6 minutes to find a parking spot in the main parking lot.
Find the work done in winding up a 175 ft cable that weighs 3 lb/ft.
Answer:
[tex]work \ done= 45937.5[/tex]
Step-by-step explanation:
Work done is given by
[tex]work \ done=\int_a^b w(d-x) \ dx[/tex] , where d = length of cable and w = weight of cable.
Here, d = 175 ft and w = 3 lb/ft
Now, [tex]work \ done=\int_0^{175} 3(175-x) \ dx[/tex]
[tex]work \ done= 3\left [175x-\frac{x^2}{2} \right ]_0^{175}[/tex]
[tex]work \ done= 3\left [175^2-\frac{175^2}{2} \right ][/tex]
[tex]work \ done= 3\cdot \frac{175^2}{2}[/tex]
[tex]work \ done= 45937.5[/tex]
which of the following number sets does 25 belong in?
2 and 4
all of the above
3 and 5
1 and 2
Answer:
all of the above
Step-by-step explanation:
The number 25 is a natural number as it belongs to the set [1,2,3,4,5,......]
The number 25 is a whole number as it belongs to the set [0,1,2,3,4,5,......]
The number 25 is an Integer as it belongs to the set [...,-5,-4,-3,-2,-1,0,1,2,3,4,5,...]
The number 25 is a rational number as it can be expressed as [tex]\[\frac{25}{1}\][/tex]
For the same reason , number 25 is a real number as it belongs to the set of rational numbers.
So the correct option is "all of the above".
25 does not belong to any of the given number sets (2 and 4, 1 and 2, or 3 and 5).
Explanation:
The number 25 does not belong to any of the provided number sets i.e. 2 and 4, 1 and 2 or 3 and 5. A number set typically refers to a collection of numbers, and in this case, 25 is absent in all the provided sets. The given number sets only contain the numbers 1, 2, 3, 4 and 5. Thus, 25 does not belong to any of these sets.
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You can buy a television for $349 cash or pay $75 down and the balance in 18 monthly payments of 22.50 is the installment price of the TV? By what percent would the installment price be greater than the cash price?
Answer:
Step-by-step explanation:
If you pay cash, the total amount that you will pay for the television is $349
If you pay $75 down, the balance would be paid in 18 monthly payments of 22.50 which is the installment price of the TV. Total amount paid in 18 months would be
22.5 × 18 = $405
Total cost of the TV when you pay in installments would be
405 + 75 = $480
Difference between the installment price and the cash price would be
480 - 349 = $131
The percent by which the installment price would be greater than the cash price is
131/349 × 100 = 37.5%
Vermont-based Green Mountain Coffee Roasters dominates the market for single-serve coffee in the United States, with its subsidiary Keurig accounting for approximately 70% of sales ("Rivals Try to Loosen Keurig's Grip on Single-Serve Coffee Market," Chicago Tribune, February 26, 2011). But Keurig's patent on K-cups, the plastic pods used to brew the coffee, is expected to expire in 2012, allowing other companies to better compete. Suppose a potential competitor has been conducting blind taste tests on its blend and finds that 47% of consumers strongly prefer its French Roast to that of Green Mountain Coffee Roasters. After tweaking its recipe, the competitor conducts a test with 144 tasters, of which 72 prefer its blend. The competitor claims that its new blend is preferred by more than 47% of consumers to Green Mountain Coffee Roasters' French Roast.
Refer to Exhibit 9-7. At the 1% significance level, does the evidence support the claim?
a. No, since the value of the test statistic is less than the critical value
b. Yes, since the value of the test statistic is less than the critical value
c. No, since the value of the test statistic is greater than the critical value
d. Yes, since the value of the test statistic is greater than the critical value
Answer:
a. No, since the value of the test statistic is less than the critical value
Step-by-step explanation:
1) Data given and notation
n=144 represent the random sample taken
X=72 represent the number of people that prefer the blend
[tex]\hat p=\frac{72}{144}=0.5[/tex] estimated proportion of people that prefer the blend
[tex]p_o=0.47[/tex] is the value that we want to test
[tex]\alpha=0.01[/tex] represent the significance level
Confidence=99% or 0.959
z would represent the statistic (variable of interest)
[tex]p_v[/tex] represent the p value (variable of interest)
2) Concepts and formulas to use
We need to conduct a hypothesis in order to test the claim that the true proportion if higher than 0.47:
Null hypothesis:[tex]p\leq 0.47[/tex]
Alternative hypothesis:[tex]p > 0.47[/tex]
When we conduct a proportion test we need to use the z statistic, and the is given by:
[tex]z=\frac{\hat p -p_o}{\sqrt{\frac{p_o (1-p_o)}{n}}}[/tex] (1)
The One-Sample Proportion Test is used to assess whether a population proportion [tex]\hat p[/tex] is significantly different from a hypothesized value [tex]p_o[/tex].
3) Calculate the statistic
Since we have all the info requires we can replace in formula (1) like this:
[tex]z=\frac{0.5 -0.47}{\sqrt{\frac{0.47(1-0.47)}{144}}}=0.721[/tex]
4) Statistical decision
We can calculate the critical value since we have a right tailed test, we need to look into the normal standard distribution a value that accumulates 0.01 of the area on the right and 0.99 on the left. And this value is:
[tex]z_{\alpha/2}=2.33[/tex]
And we can use the following excel code to find the critical value: "=NORM.INV(0.99,0,1)"
Our calculated value on this case is less than the critical value so the best conclusion is:
a. No, since the value of the test statistic is less than the critical value
For a school field trip the students had two options for lunch, a turkey or egg salad sandwich, so it is impossible for a student have both lunches. If the probability that a student chooses a turkey sandwich is 0.10, and the probability that a student chooses an egg salad sandwich is 0.67, what is the probability that a student chooses a turkey or egg salad sanwich?
Answer: 0.77
Step-by-step explanation:
Given : Probability that a student chooses a turkey sandwich is
P(Turkey )= 0.10
Probability that a student chooses an egg salad sandwich is
P(egg salad)=0.67
Also, it is impossible for a student have both lunches.
∴ P(Turkey and egg salad) =0
Now , the probability that a student chooses a turkey or egg salad sandwich will be
P(Turkey or egg salad) = P(Turkey )+ P(egg salad)- P(Turkey and egg salad)
= 0.10+ 0.67-0 = 0.77
Hence, the probability that a student chooses a turkey or egg salad sandwich= 0.77
Final answer:
The probability that a student picks either a turkey or an egg salad sandwich for their school field trip is 0.77 or 77%.
Explanation:
To calculate the probability that a student chooses either a turkey or egg salad sandwich for lunch, we use the formula for the probability of an 'or' event.
Since the options are mutually exclusive, meaning a student can only choose one type of sandwich, we simply add the individual probabilities together.
The probability of choosing a turkey sandwich is 0.10 and the probability of choosing an egg salad sandwich is 0.67.
Therefore, we can calculate it as follows:
P(turkey OR egg salad) = P(turkey) + P(egg salad)
P(turkey OR egg salad) = 0.10 + 0.67
P(turkey OR egg salad) = 0.77
So the probability that a student picks either a turkey or an egg salad sandwich is 0.77, or 77%.
A tank contains 6,000 L of brine with 16 kg of dissolved salt. Pure water enters the tank at a rate of 60 L/min. The solution is kept thoroughly mixed and drains from the tank at the same rate. (a) How much salt is in the tank after t minutes? y = kg (b) How much salt is in the tank after 20 minutes? (Round your answer to one decimal place.) y = kg
Answer:
a) [tex]S_{a}(t)=16Kg-0.16Kg*\frac{t}{min}[/tex]
b) [tex]S_{a}(20)=12.8Kg[/tex]
Step-by-step explanation:
It can be seen in the graph that the water velocity and solution velocity is the same, but the salt concentation will be lower
Water velocity [tex]V_{w} = 60\frac{L}{min}[/tex]
Solution velocity [tex]V_{s} = 60\frac{L}{min}[/tex]
Brine concentration = [tex]\frac{6,000L}{16Kg}=375\frac{L}{Kg}[/tex]
a) Amount of salt as a funtion of time Sa(t)
[tex]S_{a}(t)=16Kg-\frac{60Kg*L}{375L}*\frac{(t)}{min}=[tex]16Kg-0.16Kg*\frac{t}{min}[/tex]
b) [tex]S_{a}(20)=16Kg-0.16\frac{Kg}{min}*(20min)=16Kg-3.2Kg=12.8Kg[/tex]
This value was to be expected since as the time passes the concentration will be lower due to the entrance to the pure water tank
To calculate the amount of salt in the tank after a certain amount of time, we need to consider the rate at which salt enters and leaves the tank. The rate of salt entering the tank is given as 60 L/min and the total volume of the tank is 6000 L. Using these values, we can find the rate of salt entering the tank in kg/min and then calculate the amount of salt in the tank after a specific time.
Explanation:To calculate the amount of salt in the tank after a certain amount of time, we need to consider the rate at which salt enters and leaves the tank. The rate of salt entering the tank is given as 60 L/min and the total volume of the tank is 6000 L. Using these values, we can find the rate of salt entering the tank in kg/min:
Rate of salt entering = (60 L/min) * (16 kg/6000 L) = 0.16 kg/min
Therefore, the amount of salt in the tank after t minutes is given by:
y = 0.16 kg/min * t min = 0.16t kg
A farmer uses a lot of fertilizer to grow his crops. The farmer’s manager thinks fertilizer products from distributor A contain more of the nitrogen that his plants need than distributor B’s fertilizer does. He takes two independent samples of four batches of fertilizer from each distributor and measures the amount of nitrogen in each batch. Fertilizer from distributor A contained 23 pounds per batch and fertilizer from distributor B contained 18 pounds per batch. Suppose the population standard deviation for distributor A and distributor B is four pounds per batch and five pounds per batch, respectively. Assume the distribution of nitrogen in fertilizer is normally distributed. Let µ1and µ2 represent the average amount of nitrogen per batch for fertilizer’s A and B, respectively. Which of the following is the appropriate conclusion at the 5% significance level? The test statistic calculated in Excel with these data is 1.5617.
Answer:
[tex]z=\frac{(23-18)-0}{\sqrt{\frac{4^2}{4}+\frac{5^2}{4}}}}=1.5617[/tex]
[tex]p_v =P(Z>1.5617)=0.059[/tex]
If we compare the p value and the significance level given [tex]\alpha=0.05[/tex] we see that [tex]p_v>\alpha[/tex] so we can conclude that we have enough evidence to FAIL to reject the null hypothesis, and the difference between the true mean of group A and B is not significantly higher than 0 at 5% of significance.
Step-by-step explanation:
Data given and notation
[tex]\bar X_{A}=23[/tex] represent the mean for the sample A
[tex]\bar X_{B}=18[/tex] represent the mean for the sample B
[tex]\sigma_{A}=4[/tex] represent the population standard deviation for the sample A
[tex]\sigma_{B}=5[/tex] represent the population standard deviation for the sample B
[tex]n_{A}=4[/tex] sample size selected A
[tex]n_{B}=4[/tex] sample size selected B
[tex]\alpha=0.05[/tex] represent the significance level for the hypothesis test.
z would represent the statistic (variable of interest)
[tex]p_v[/tex] represent the p value for the test (variable of interest)
State the null and alternative hypotheses.
We need to conduct a hypothesis in order to check if the mean for A is higher than the mean for B, the system of hypothesis would be:
Null hypothesis:[tex]\mu_{A}-\mu_{B}\leq 0[/tex]
Alternative hypothesis:[tex]\mu_{A}-\mu_{B}>0[/tex]
We know the population deviations, so for this case is better apply a z test to compare means, and the statistic is given by:
[tex]z=\frac{(\bar X_{A}-\bar X_{B})-0}{\sqrt{\frac{\sigma^2_{A}}{n_{A}}+\frac{\sigma^2_{B}}{n_{B}}}}[/tex] (1)
z-test: "Is used to compare group means. Is one of the most common tests and is used to determine whether the means of two groups are equal to each other".
Calculate the statistic
We can replace in formula (1) the info given like this:
[tex]z=\frac{(23-18)-0}{\sqrt{\frac{4^2}{4}+\frac{5^2}{4}}}}=1.5617[/tex]
P-value
Since is a one right tailed test the p value would be:
[tex]p_v =P(Z>1.5617)=0.059[/tex]
Conclusion
If we compare the p value and the significance level given [tex]\alpha=0.05[/tex] we see that [tex]p_v>\alpha[/tex] so we can conclude that we have enough evidence to FAIL to reject the null hypothesis, and the difference between the true mean of group A and B is not significantly higher than 0 at 5% of significance.
To determine the appropriate conclusion at the 5% significance level, conduct a hypothesis test for the difference in means between the two fertilizer distributors.
Explanation:To determine the appropriate conclusion at the 5% significance level, we need to conduct a hypothesis test for the difference in means between the two fertilizer distributors. The test statistic calculated in Excel is 1.5617. We compare this test statistic to the critical value of the t-distribution at the desired significance level of 5% with 6 degrees of freedom (8 samples - 2). If the test statistic is greater than the critical value, we reject the null hypothesis that the means are equal and conclude that there is evidence to suggest that distributor A's fertilizer contains more nitrogen than distributor B's.
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Consider the function shown. A segment extends from negative 5 comma 0 to negative 2 comma 5. A segment extends from negative 2 comma 5 to 1 comma 5. A segment extends from 1 comma 5 to 8 comma negative 2. Where is the function decreasing? Enter your answer in the boxes. The function is decreasing from x = to x = .
Answer: The function is constant from x = -2 to x=1
Final answer:
The function is decreasing from x = 1 to x = 8, as the segment in that interval shows a decrease in y values as x increases.
Explanation:
To determine where the function is decreasing, we need to look at the segments provided. A function is decreasing if, as x increases, the y value of the function decreases. From the description of the segments, we can analyze behavior in each interval:
The first segment extends from x = -5 to x = -2 and ascends from a y-value of 0 to 5, which means the function is increasing in this interval.The second segment stretches from x = -2 to x = 1 and remains at a consistent y-value of 5, indicating a horizontal line and therefore, the function is neither increasing nor decreasing.The final segment extends from x = 1 to x = 8, moving from a y-value of 5 to -2. During this segment, as x increases, y decreases, which clearly marks this interval as a decreasing interval for the function.Therefore, the function is decreasing from x = 1 to x = 8.
Find a solution to the following initial-value problem: dy dx = y(y − 2)e x , y (0) = 1.
This equation is separable, as
[tex]\dfrac{\mathrm dy}{\mathrm dx}=y(y-2)e^x\implies\dfrac{\mathrm dy}{y(y-2)}=e^x\,\mathrm dx[/tex]
Integrate both sides; on the left, expand the fraction as
[tex]\dfrac1{y(y-2)}=\dfrac12\left(\dfrac1{y-2}-\dfrac1y\right)[/tex]
Then
[tex]\displaystyle\int\frac{\mathrm dy}{y(y-2)}=\int e^x\,\mathrm dx\implies\frac12(\ln|y-2|-\ln|y|)=e^x+C[/tex]
[tex]\implies\dfrac12\ln\left|\dfrac{y-2}y\right|=e^x+C[/tex]
Since [tex]y(0)=1[/tex], we get
[tex]\dfrac12\ln\left|\dfrac{1-2}1\right|=e^0+C\implies C=-1[/tex]
so that the particular solution is
[tex]\dfrac12\ln\left|\dfrac{y-2}y\right|=e^x-1\implies\boxed{y=\dfrac2{1-e^{2e^x-2}}}[/tex]
The paint used to make lines on roads must reflect enough light to be clearly visible at night. Let µ denote the true average reflectometer reading for a new type of paint under consideration. A test of H0: µ = 20 versus Ha: µ > 20 will be based on a random sample of size n from a normal population distribution. What conclusion is appropriate in each of the following situations? (Round your P-values to three decimal places.)(a) n = 16, t = 3.3, a = 0.05P-value =(b) n = 8, t = 1.8, a = 0.01P-value =(c) n = 26,t = -0.6P-value =
Answer:
a) [tex]df=n-1=16-1=15[/tex]
The statistic calculated is given by t=3.3
Since is a one-side upper test the p value would be:
[tex]p_v =P(t_{15}>3.3)=0.0024[/tex]
So since the p value is lower than the significance level [tex]pv<\alpha[/tex] we reject the null hypothesis.
b) [tex]df=n-1=8-1=7[/tex]
The statistic calculated is given by t=1.8
Since is a one-side upper test the p value would be:
[tex]p_v =P(t_{7}>1.8)=0.057[/tex]
So since the p value is higher than the significance level [tex]pv>\alpha[/tex] we FAIL to reject the null hypothesis.
c) [tex]df=n-1=26-1=25[/tex]
The statistic calculated is given by t=-0.6
Since is a one-side upper test the p value would be:
[tex]p_v =P(t_{25}>-0.6)=0.723[/tex]
So since the p value is higher than the significance level [tex]pv>\alpha[/tex] we FAIL to reject the null hypothesis.
Step-by-step explanation:
1) Data given and notation
[tex]\bar X[/tex] represent the sample mean
[tex]s[/tex] represent the standard deviation for the sample
[tex]n[/tex] sample size
[tex]\mu_o =20[/tex] represent the value that we want to test
[tex]\alpha[/tex] represent the significance level for the hypothesis test.
t would represent the statistic (variable of interest)
[tex]p_v[/tex] represent the p value for the test (variable of interest)
State the null and alternative hypotheses.
We need to conduct a hypothesis in order to determine if the true mean is higher than 20, the system of hypothesis would be:
Null hypothesis:[tex]\mu \leq 20[/tex]
Alternative hypothesis:[tex]\mu > 20[/tex]
We don't know the population deviation, so for this case is better apply a t test to compare the actual mean to the reference value, and the statistic is given by:
[tex]t=\frac{\bar X-\mu_o}{\frac{s}{\sqrt{n}}}[/tex] (1)
t-test: "Is used to compare group means. Is one of the most common tests and is used to determine if the mean is (higher, less or not equal) to an specified value".
(a) n = 16, t = 3.3, a = 0.05, P-value =
First we need to calculate the degrees of freedom given by:
[tex]df=n-1=16-1=15[/tex]
The statistic calculated is given by t=3.3
Since is a one-side upper test the p value would be:
[tex]p_v =P(t_{15}>3.3)=0.0024[/tex]
So since the p value is lower than the significance level [tex]pv<\alpha[/tex] we reject the null hypothesis.
(b) n = 8, t = 1.8, a = 0.01, P-value =
First we need to calculate the degrees of freedom given by:
[tex]df=n-1=8-1=7[/tex]
The statistic calculated is given by t=1.8
Since is a one-side upper test the p value would be:
[tex]p_v =P(t_{7}>1.8)=0.057[/tex]
So since the p value is higher than the significance level [tex]pv>\alpha[/tex] we FAIL to reject the null hypothesis.
(c) n = 26,t = -0.6, P-value =
First we need to calculate the degrees of freedom given by:
[tex]df=n-1=26-1=25[/tex]
The statistic calculated is given by t=-0.6
Since is a one-side upper test the p value would be:
[tex]p_v =P(t_{25}>-0.6)=0.723[/tex]
So since the p value is higher than the significance level [tex]pv>\alpha[/tex] we FAIL to reject the null hypothesis.
The P-value helps decide whether to reject the null hypothesis in a t-test. If the P-value is less than the significance level α, the null hypothesis is rejected. For each given scenario, the P-value is found from the t-distribution considering the provided t-statistic and degrees of freedom (n-1).
Explanation:The problem is about conducting a t-test to check if the reflectometer reading (μ) for a new type of road paint is greater than a specified value (20). The P-value of the t-test will tell us if we should reject the null hypothesis H0: μ = 20 in favor of the alternative hypothesis Ha: μ > 20. The P-value is the probability of observing a t-score as extreme as the one calculated from the sample data (or more extreme), given that the null hypothesis is true.
(a) For n = 16, t = 3.3, and α = 0.05, we can use the t-distribution table or a statistical software to find the P-value. Since t is positive and we are dealing with a one-tailed test (because Ha: μ > 20), the P-value is the area to the right of the t-score (3.3) under the t-distribution. If the calculated P-value is less than α (0.05), we reject the null hypothesis.
(b) The same process applies for n = 8, t = 1.8, and α = 0.01. However, due to the smaller α level, we would need a larger t statistic (and thus a smaller P-value) to reject the null hypothesis.
(c) For n = 26, t = -0.6, if the calculated P-value is greater than the chosen α value, we do not reject the null hypothesis believing that the true mean reflectometer reading is 20.
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The Wall Street Journal Corporate Perceptions Study 2011 surveyed readers and asked how each rated the Quality of Management and the Reputation of the Company for over 250 world-wide corporations. Both the Quality of Management and the Reputation of the Company were rated on an Excellent, Good, and Fair categorical scale. Assume the sample data for 200 respondents below applies to this study.
Col1 Quality of Management Excellent Good Fair
Col2 Excellent 40 35 25
Col3 Good 25 35 10
Col4 Fair 5 10 15
Use a .05 level of significance and test for independence of the quality of management and the reputation of the company.
Compute the value of the 2 test statistic (to 2 decimals).
The p-value is
What is your conclusion?
b. If there is a dependence or association between the two ratings, discuss and use probabilities to justify your answer.
Answer:
a)[tex]\chi^2 = \frac{(40-35)^2}{35}+\frac{(35-40)^2}{40}+\frac{(25-25)^2}{25}+\frac{(25-24.5)^2}{24.5}+\frac{(35-28)^2}{28}+\frac{(25-17.5)^2}{17.5}+\frac{(5-10.5)^2}{10.5}+\frac{(10-12)^2}{12}+\frac{(15-7.5)^2}{7.5} =17.03[/tex]
[tex]p_v = P(\chi^2_{4} >17.03)=0.0019[/tex]
And we can find the p value using the following excel code:
"=1-CHISQ.DIST(17.03,4,TRUE)"
Since the p value is lower than the significance level we can reject the null hypothesis at 5% of significance, and we can conclude that we have association or dependence between the two variables.
b)
P(E|Ex)= P(EΛEx )/ P(Ex) = (40/215)/ (70/215)= 40/70=0.5714
P(E|Gx)= P(EΛGx )/ P(Gx) = (35/215)/ (80/215)= 35/80=0.4375
P(E|Fx)= P(EΛFx )/ P(Fx) = (25/215)/ (50/215)= 25/50=0.5
P(G|Ex)= P(GΛEx )/ P(Ex) = (25/215)/ (70/215)= 25/70=0.357
P(G|Gx)= P(GΛGx )/ P(Gx) = (35/215)/ (80/215)= 35/80=0.4375
P(G|Fx)= P(GΛFx )/ P(Fx) = (10/215)/ (50/215)= 10/50=0.2
P(F|Ex)= P(FΛEx )/ P(Ex) = (5/215)/ (70/215)= 5/70=0.0714
P(F|Gx)= P(FΛGx )/ P(Gx) = (10/215)/ (80/215)= 10/80=0.125
P(F|Fx)= P(FΛFx )/ P(Fx) = (15/215)/ (50/215)= 15/50=0.3
And that's what we see here almost all the conditional probabilities are higher than 0.2 so then the conclusion of dependence between the two variables makes sense.
Step-by-step explanation:
A chi-square goodness of fit test "determines if a sample data matches a population".
A chi-square test for independence "compares two variables in a contingency table to see if they are related. In a more general sense, it tests to see whether distributions of categorical variables differ from each another".
Assume the following dataset:
Quality management Excellent Good Fair Total
Excellent 40 35 25 100
Good 25 35 10 70
Fair 5 10 15 30
Total 70 80 50 200
Part a
We need to conduct a chi square test in order to check the following hypothesis:
H0: There is independence between the two categorical variables
H1: There is association between the two categorical variables
The level of significance assumed for this case is [tex]\alpha=0.05[/tex]
The statistic to check the hypothesis is given by:
[tex]\chi^2 = \sum_{i=1}^n \frac{(O_i -E_i)^2}{E_i}[/tex]
The table given represent the observed values, we just need to calculate the expected values with the following formula [tex]E_i = \frac{total col * total row}{grand total}[/tex]
And the calculations are given by:
[tex]E_{1} =\frac{70*100}{200}=35[/tex]
[tex]E_{2} =\frac{80*100}{200}=40[/tex]
[tex]E_{3} =\frac{50*100}{200}=25[/tex]
[tex]E_{4} =\frac{70*70}{200}=24.5[/tex]
[tex]E_{5} =\frac{80*70}{200}=28[/tex]
[tex]E_{6} =\frac{50*70}{200}=17.5[/tex]
[tex]E_{7} =\frac{70*30}{200}=10.5[/tex]
[tex]E_{8} =\frac{80*30}{200}=12[/tex]
[tex]E_{9} =\frac{50*30}{200}=7.5[/tex]
And the expected values are given by:
Quality management Excellent Good Fair Total
Excellent 35 40 25 100
Good 24.5 28 17.5 85
Fair 10.5 12 7.5 30
Total 70 80 65 215
And now we can calculate the statistic:
[tex]\chi^2 = \frac{(40-35)^2}{35}+\frac{(35-40)^2}{40}+\frac{(25-25)^2}{25}+\frac{(25-24.5)^2}{24.5}+\frac{(35-28)^2}{28}+\frac{(25-17.5)^2}{17.5}+\frac{(5-10.5)^2}{10.5}+\frac{(10-12)^2}{12}+\frac{(15-7.5)^2}{7.5} =17.03[/tex]
Now we can calculate the degrees of freedom for the statistic given by:
[tex]df=(rows-1)(cols-1)=(3-1)(3-1)=4[/tex]
And we can calculate the p value given by:
[tex]p_v = P(\chi^2_{4} >17.03)=0.0019[/tex]
And we can find the p value using the following excel code:
"=1-CHISQ.DIST(17.03,4,TRUE)"
Since the p value is lower than the significance level we can reject the null hypothesis at 5% of significance, and we can conclude that we have association or dependence between the two variables.
Part b
We can find the probabilities that Quality of Management and the Reputation of the Company would be the same like this:
Let's define some notation first.
E= Quality Management excellent Ex=Reputation of company excellent
G= Quality Management good Gx=Reputation of company good
F= Quality Management fait Ex=Reputation of company fair
P(EΛ Ex) =40/215=0.186
P(GΛ Gx) =35/215=0.163
P(FΛ Fx) =15/215=0.0697
If we have dependence then the conditional probabilities would be higher values.
P(E|Ex)= P(EΛEx )/ P(Ex) = (40/215)/ (70/215)= 40/70=0.5714
P(E|Gx)= P(EΛGx )/ P(Gx) = (35/215)/ (80/215)= 35/80=0.4375
P(E|Fx)= P(EΛFx )/ P(Fx) = (25/215)/ (50/215)= 25/50=0.5
P(G|Ex)= P(GΛEx )/ P(Ex) = (25/215)/ (70/215)= 25/70=0.357
P(G|Gx)= P(GΛGx )/ P(Gx) = (35/215)/ (80/215)= 35/80=0.4375
P(G|Fx)= P(GΛFx )/ P(Fx) = (10/215)/ (50/215)= 10/50=0.2
P(F|Ex)= P(FΛEx )/ P(Ex) = (5/215)/ (70/215)= 5/70=0.0714
P(F|Gx)= P(FΛGx )/ P(Gx) = (10/215)/ (80/215)= 10/80=0.125
P(F|Fx)= P(FΛFx )/ P(Fx) = (15/215)/ (50/215)= 15/50=0.3
And that's what we see here almost all the conditional probabilities are higher than 0.2 so then the conclusion of dependence between the two variables makes sense.
what transformations are represented by the following coordinate graphing? (geometry)
(a,b) --> (a,-b)
(a,b) --> (a, b+5)
(a,b) --> (b,-a)
Answer:
(a,b) → (a,-b) : Reflection about x axis.
(a,b) → (a, b+5) : Translation of the point by 5 units up.
(a,b) → (b,-a) : Rotation by 90 degree clockwise.
Step-by-step explanation:
Given:
The transformation of points are given as:
(a,b) → (a,-b)
(a,b) → (a, b+5)
(a,b) → (b,-a)
Now, let us consider each transformation one by one.
(1) (a,b) → (a,-b)
Here, the order of the coordinates has not changed. But, the y coordinate of the point has changed. The y coordinate was 'b' and it has changed only its sign but not value. So, it is a transformation related to reflection.
In reflection, only the sign changes. Since, the 'y' coordinate sing is reversed, so, it is a reflection about x axis.
(2) (a,b) → (a, b+5)
Here, the 'y' coordinate of the point has changed. The change is from 'b' to 'b+5'. So, 5 is added to the y coordinate. As per transformation rules, if a positive number 'C' is added to the y coordinate, then the point shifts vertically up by 'C' units. Hence, there is a translation of 5 units up here.
(3) (a,b) → (b,-a)
Here, the 'x' and 'y' coordinates interchange their values and also the new y coordinate has its sign reversed. This happens in rotation.
We know that, (x, y) → (y, –x) is true when there is rotation by 90 degree clockwise.
So, the point (a,b) → (b,-a) is rotated by 90 degree clockwise.
When hypothesis testing, when might you use a related sample versus an independent sample? Provide examples of both population to illustrate the differences.
Answer:
The key difference is that the dependent sample test uses usually the same individuals to obtain the info for two different moments. And the independent sample test uses two different groups in order to compare a parameter on specific, usually the mean.
Step-by-step explanation:
A paired t-test is used to compare two population means when we have two samples in which observations in one sample can be paired with observations in the other sample. For example if we have Before-and-after observations in order to see an improvement or not for a method we can use it ( Without treatment and With specific treatment).
An independent sample test is used when we want to compare "two sample means to determine whether the population means are significantly different". For example if we want to compare the scores for male and female in a test.
The key difference is that the dependent sample test uses usually the same individuals to obtain the info for two different moments. And the independent sample test uses two different groups in order to compare a parameter on specific, usually the mean.
When conducting hypothesis testing, the choice between using a related sample or an independent sample depends on the nature of the data being analyzed. A related sample is used when the two samples are dependent or paired, while an independent sample is used when the two samples are not related and can be considered as separate groups.
Explanation:When conducting hypothesis testing, the choice between using a related sample or an independent sample depends on the nature of the data being analyzed. A related sample is used when the two samples are dependent or paired, meaning that there is a one-to-one correspondence between the data points in the two samples. An independent sample is used when the two samples are not related and can be considered as separate groups.
For example, in a related sample scenario, you might compare the blood pressure of the same group of individuals before and after a treatment. The paired samples would be the pre-treatment and post-treatment measurements of each individual. In an independent sample scenario, you might compare the test scores of two different groups of students who were taught using different teaching methods.
The profile of the cables on a suspension bridge may be modeled by a parabola. The central span of a bridge is 1270 ft long and 157 ft high. The parabola y=0.00039x^2 gives a good fit to the shape of the cables, where IxI less than of equal to 635, and x and y are measured in feet. Approximate the length of the cables that stretch between the tops of the two towers.
Answer:
Step-by-step explanation:
Given
span of bridge [tex]L=1270\ ft[/tex]
height of span [tex]h=157\ ft[/tex]
Equation of Parabola
[tex]y=0.00039x^2[/tex]
[tex]|x|<635[/tex] i.e.
[tex]-635<x<635[/tex]
[tex]\frac{dy}{dx}=2\times 0.00039[/tex]
length of Arc[tex]=\int_{a}^{b}\sqrt{1+(\frac{dy}{dx})^2}[/tex]
[tex]=\int_{-635}^{635}\sqrt{1+(\frac{dy}{dx})^2}[/tex]
[tex]=\int_{-635}^{635}\sqrt{1+(0.00078x)^2}[/tex]
[tex]=2\times \int_{0}^{635}\sqrt{1+(0.00078x)^2}[/tex]
[tex]=2\times (660.08)[/tex]
[tex]=1320.16\ ft[/tex]
The approximate length of the cables is approximately 4534.24 feet.
To approximate the length of the cables that stretch between the tops of the two towers of the suspension bridge, we can use the integral calculus to find the length of the curve defined by the equation [tex]\(y = 0.00039x^2\).[/tex]
The formula for finding the length of a curve between two points [tex]\([a, b]\)[/tex] is given by the integral:
[tex]\[L = \int_{a}^{b} \sqrt{1 + (f'(x))^2} \, dx\][/tex]
Where:
- L is the length of the curve.
- a and b are the x-coordinates of the two points between which we want to find the length.
- f(x) is the function representing the curve.
- f'(x) is the derivative of the function.
In this case, we want to find the length of the cables between the two towers, which corresponds to the x-values from -635 to 635 since the width of the bridge is 1270 feet. The curve is defined by [tex]\(y = 0.00039x^2\)[/tex], so:
- a = -635
- b = 635
- [tex]\(f(x) = 0.00039x^2\)[/tex]
- [tex]\(f'(x) = 2 \cdot 0.00039x\)[/tex]
Now, let's calculate the length:
[tex]\[L = \int_{-635}^{635} \sqrt{1 + (2 \cdot 0.00039x)^2} \, dx\][/tex]
[tex]\[L = \int_{-635}^{635} \sqrt{1 + 0.0001536x^2} \, dx\][/tex]
Now, we can evaluate this integral:
[tex]\[L = \int_{-635}^{635} \sqrt{1 + 0.0001536x^2} \, dx \approx 4534.24\][/tex]
So, the approximate length of the cables that stretch between the tops of the two towers of the suspension bridge is approximately 4534.24 feet.
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The price of a certain security follows a geometric Brownian motion with drift parameter µ = 0.12 and the volatility parameter σ = 0.24.
(a) If the current price of the security is $40, find the probability that a call option, having four months until expiration and with a strike price of K = 42 will be exercised.
(b) In addition to the above information as in part (a) if the interest rate is 8%, find the risk-neutral arbitrage free valuation of the call option.
Answer:
Brownian Motion- The usual model for the time-evolution of an asset price S(t) is given by the geometric Brownian motion.
Now the geometric Brownian motion is represented by the following stochastic differential equation:
dS(t)=μS(t)dt+σS(t)dB(t)Note- coefficients μ representing the drift and σ,volatility of the asset, respectively, are both constant in this model.To solve the problem now we have the been Data provided:
μ= 0.12,
σ=0.24,
Step-by-step explanation:
Step A:
we have, the variables of Black Scholes Model, by putting the values of variables available, we get:
S = Current stock price = 40 ,
K = Strike Price = 42 ,
Next is, "r" the risk free rate,
risk free rate, r = mu = 0.12 ,
Volatility, σ = 0.24
time to maturity, T, as we have;T= 4 months = 4/12.T = 1/3 year(360 days)
Step B:
We now need to calculate the parameter d₂ of the Black Scholes Model. .
The probability which we want is 1 - N(-d₂),So, we have;d₂=㏑(S/K)+(r-σ²/2)T/σ√T
Step C:
As step C is done on excel for further calculations so, do use it if you are solving it on computer.
Final answer:
To find the probability that a call option will be exercised and the risk-neutral arbitrage-free valuation of the call option, we can use the Black-Scholes-Merton model and the risk-neutral pricing framework respectively.
Explanation:
To find the probability that a call option will be exercised, we can use the Black-Scholes-Merton model. In this case, we have:
The current price of the security (S) = $40
The strike price of the option (K) = $42
The time to expiration (T) = 4 months (or 0.33 years)
The risk-free interest rate (r) = 8% (or 0.08)
The volatility of the security (σ) = 0.24
Using these values, we can plug them into the Black-Scholes-Merton formula to calculate the probability of the call option being exercised.
For part (b), we can use the risk-neutral pricing framework to calculate the arbitrage-free valuation of the call option. This involves discounting the expected future payoff of the option at the risk-free interest rate.
To calculate the risk-neutral valuation, we use the same values as in part (a) and discount the expected payoff to the present value using the risk-free interest rate.
Resistors are labeled 100 Ω. In fact, the actual resistances are uniformly distributed on the interval (95, 103). Find the mean resistance. Find the standard deviation of the resistances. Find the probability that the resistance is between 98 and 102 Ω. Suppose that resistances of different resistors are independent. What is the probability that three out of six resistors have resistances greater than 100 Ω?
Answer:
[tex]E[R][/tex] = 99 Ω
[tex]\sigma_R[/tex] = 2.3094 Ω
P(98<R<102) = 0.5696
Step-by-step explanation:
The mean resistance is the average of edge values of interval.
Hence,
The mean resistance, [tex]E[R] = \frac{a+b}{2} = \frac{95+103}{2} = \frac{198}{2}[/tex] = 99 Ω
To find the standard deviation of resistance, we need to find variance first.
[tex]V(R) = \frac{(b-a)^2}{12} =\frac{(103-95)^2}{12} = 5.333[/tex]
Hence,
The standard deviation of resistance, [tex]\sigma_R = \sqrt{V(R)} = \sqrt5.333[/tex] = 2.3094 Ω
To calculate the probability that resistance is between 98 Ω and 102 Ω, we need to find Normal Distributions.
[tex]z_1 = \frac{102-99}{2.3094} = 1.299[/tex]
[tex]z_2 = \frac{98-99}{2.3094} = -0.433[/tex]
From the Z-table, P(98<R<102) = 0.9032 - 0.3336 = 0.5696
In a group of mherchants, 80% of them purchase goods from Asia, and 25% of them purchase goods from Europe. Which of following statement is individually sufficient to calculate what percent of the merchants in the group purchase goods from Europe but not form Asia? 7. 25% of the merchants who purchase goods from Asia also purchase from Europe. 15% of all merchants purchase goods from neither Asia nor Europe 0% of all merchants purchase good from both Asia and Europe
Answer:
7. 25% of the merchants who purchase goods from Asia also purchase from Europe.
Step-by-step explanation:
I am going to say that:
A is the percentage of merchants who purchase goods from Asia.
B is the percentage of merchants who purchase goods from Europe.
We have that:
[tex]A = a + (A \cap B)[/tex]
In which a is the probability that a merchant purchases goods from Asia but not from Europe and [tex]A \cap B[/tex] is the probability that a merchant purchases goods from both Asia and Europe.
By the same logic, we have that:
[tex]B = b + (A \cap B)[/tex]
Which of following statement is individually sufficient to calculate what percent of the merchants in the group purchase goods from Europe but not form Asia?
We already have B.
Knowing [tex]A \cap B[/tex], that is, the percentage of those who purchase from both Asia and Europe, we can find b.
So the correct answer is:
7. 25% of the merchants who purchase goods from Asia also purchase from Europe.
In a random sample of 9 residents of the state of Florida, the mean waste recycled per person per day was 2.4 pounds with a standard deviation of 0.75 pounds. Determine the 80% confidence interval for the mean waste recycled per person per day for the population of Florida. Assume the population is approximately normal. Step 1 of 2 : Find the critical value that should be used in constructing the confidence interval. Round your answer to three decimal places.
When the sample size is small (< 30) and the population standard deviation is unknown , then we use t-test.
The confidence interval for population mean will be :
[tex]\overline{x}\pm t^*\dfrac{s}{\sqrt{n}}[/tex] (1)
, where [tex]\overline{x}[/tex] = sample mean
t* = Critical value (based on degree of freedom and significance level).
s= sample standard deviation
n= sample size.
As per given we have
n= 9
Degree of freedom = n-1 = 8
[tex]\overline{x}=2.4[/tex]
s= 0.75
Significance level =[tex]\alpha=1-0.80=0.20[/tex]
Using students' t distribution table ,
Critical value : [tex]t^*=t_{\alpha/2,df}=t_{0.10,8}=1.3304[/tex]
We assume that the population is approximately normal.
Then, a 80% confidence interval for the mean waste recycled per person per day for the population of Florida will be :
[tex]2.4\pm (1.3304)\dfrac{0.75}{\sqrt{8}}[/tex] (Substitute the values in (1))
[tex]2.4\pm (1.3304)\dfrac{0.75}{2.82842712475}[/tex]
[tex]2.4\pm (1.3304)(0.265165042945)[/tex]
[tex]2.4\pm 0.352775573134\approx2.4\pm0.353=(2.4-0.353,\ 2.4+0.353)=(2.047,\ 2.753)[/tex]
Hence, the 80% confidence interval for the mean waste recycled per person per day for the population of Florida. = (2.047, 2.753)
two circles have circumferences of (8xy) cm and (5xy) cm respectively. what is the variable expression to represent the sum of their circumferences?
(8xy)cm X (5xy)cm
(8xy)cm - (5xy)cm
(8xy)cm + (5xy)cm
(8xy)cm divided by (5xy)cm
Answer:the variable expression to represent the sum of their circumferences would be
(8xy)cm + (5xy)cm
Step-by-step explanation:
The circumference of the first circle is 8xy cm
The circumference of the second circle is 5xy cm
the variable expression to represent the sum of their circumferences would be
(8xy)cm + (5xy)cm
This variable expression can also be simplified further because both terms contain xy.
The scale drawing has a scale of 1/2 in: 8 mi. Find the length on the drawing for 2 in Please answer asap
Answer:
32 mi
Step-by-step explanation:
Solve using proportions.
[tex]\frac{\frac{1}{2}in}{8 mi} =\frac{2in}{y}[/tex]
Find the scale factor (how to get from left to right)
To get from left numerator to right numerator, multiply by 4.
(1/2) X 4 = 2
The scale factor is 4.
Multiply the left denominator by the scale factor to get "y".
8 mi X 4 = 32 mi
Therefore 2 inches represent 32 miles.
A political scientist wants to know how college students feel about the social security system. She obtains a list of the 3114 undergraduates at her college and mails a questionnaire to 250 students selected at random. Only 100 of the questionnaires are returned. In this study, the rate of non-response would be a. 0.25. b. 0.40. x. 0.75. d. 0.60
Answer: d. 0.60
Step-by-step explanation:
When are performing sample surveys , when the selected participant is giving any response is denoted as non - response.
The proportion of these participants of the sample is known as the non-response rate.
Given : A political scientist wants to know how college students feel about the social security system.
She obtains a list of the 3114 undergraduates at her college and mails a questionnaire to 250 students selected at random.
i.e. Sample size : n= 290
Only 100 of the questionnaires are returned.
Individual gave response =100
Individual gave no-response =250-100 =150
The rate of non-response [tex]=\dfrac{\text{Individual gave no-response}}{n}[/tex]
[tex]=\dfrac{150}{250} =0.60[/tex]
Hence, the rate of non-response would be 0.60 .
Thus , the correct option is d. 0.60.
Suppose that nine bats was used. For each trail, the zoo keeper pointed to one of two "feeders" Suppose that the bats went to the correct feeder (the one that the zoo keeper pointed at) 7 times. Find the 95% confidence interval for the population proportion of times that the bats would follow the point.
A. (0.59, 1.05)
B. (0.44,0.94)C. (0.51, 1.0)
Answer: B. (0.44,0.94)
Step-by-step explanation:
Given : Number of observations : n = 9
Number of successes : x = 7
Let p be the population proportion of times that the bats would follow the point.
Since the sample size is small , so we use plus four confidence interval for p.
Plus four estimate of p=[tex]\hat{p}=\dfrac{\text{No. of successes}+2}{\text{No. of observations}+4}[/tex]
[tex]=\dfrac{7+2}{9+4}\approx0.69[/tex]
By z-table , the critical value for 95% confidence level : z* = 1.96
Then, the 95% confidence interval for the population proportion of times that the bats would follow the point. will be :
[tex]\hat{p}\pm z^*\sqrt{\dfrac{\hat{p}(1-\hat{p})}{N}}[/tex] , where N= 13
[tex]0.69\pm (1.96)\sqrt{\dfrac{0.69(1-0.69)}{13}}[/tex]
[tex]0.69\pm (1.96)\sqrt{0.0163862084615}[/tex]
[tex]0.69\pm (1.96)(0.128008626512)[/tex]
[tex]\approx0.69\pm 0.25=(0.69-0.25,\ 0.69+0.25)[/tex]
[tex](0.44,\ 0.94)[/tex]
Hence, the 95% confidence interval for the population proportion of times that the bats would follow the point = [tex](0.44,\ 0.94)[/tex]
Thus the correct answer is B. (0.44,0.94)
To find the 95% confidence interval for the population proportion, use the formula CI = p ± z * √((p(1-p))/n), where p is the sample proportion, z is the z-score, and n is the sample size. Substituting values, the 95% confidence interval is approximately (0.685, 0.869).
Explanation:To find the 95% confidence interval for the population proportion, we can use the formula:
CI = p ± z * √((p(1-p))/n)
where p is the sample proportion, z is the z-score for the desired confidence level, and n is the sample size.
In this case, the sample proportion is 7/9 and n is 9. Since we want a 95% confidence interval, the z-score is approximately 1.96.
Substituting these values into the formula:
CI = (7/9) ± 1.96 * √(((7/9)(2/9))/9)
CI = 0.777 ± 1.96 * √(0.123/9)
CI ≈ 0.777 ± 1.96 * 0.047
CI ≈ (0.777 - 0.092, 0.777 + 0.092)
CI ≈ (0.685, 0.869)
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The PCB concentration of a fish caught in Lake Michigan was measured by a technique that is known to result in an error of measurement that is normally distributed with a standard deviation of .08 ppm (parts per million). Suppose the results of 10 independent measurements of this fish are 11.2, 12.4, 10.8, 11.6, 12.5, 10.1, 11.0, 12.2, 12.4, 10.6(a) Give a 95 percent confidence interval for the PCB level of this fish.(b) Give a 95 percent lower confidence interval.(c) Give a 95 percent upper confidence interval.
Final answer:
The 95% confidence interval for the PCB level in the fish is (11.4228, 11.5372) ppm. The 95% lower confidence interval is 11.4228 ppm and the 95% upper confidence interval is 11.5372 ppm, based on both the t-distribution and the provided sample data and standard deviation.
Explanation:
To find the 95% confidence interval, lower confidence interval, and upper confidence interval of the PCB level in a fish from Lake Michigan, based on 10 measurements and a standard deviation of 0.08 ppm, we first need to calculate the sample mean and then apply the appropriate formulas.
To calculate the mean PCB concentration (μ), we sum all the values and divide by the number of measurements (n=10):
μ = (11.2 + 12.4 + 10.8 + 11.6 + 12.5 + 10.1 + 11.0 + 12.2 + 12.4 + 10.6) / 10 = 114.8 / 10 = 11.48 ppm.
For calculating the confidence intervals, we use the t-distribution since the sample size is small. We need the t-value for 9 degrees of freedom (n-1) at the 95% confidence level which, assuming it is approximately 2.262 (values differ slightly depending on the t-distribution table used).
The standard error (SE) is calculated using the sample standard deviation (s) and the square root of the number of measurements: SE = s/sqrt(n) = 0.08/sqrt(10) = 0.0253 ppm.
The 95% confidence interval is given by:
CI = μ ± (t-value * SE)
CI = 11.48 ± (2.262 * 0.0253)
CI = 11.48 ± 0.0572
CI = (11.4228, 11.5372) ppm
The 95% lower confidence interval is the mean minus the product of the t-value and SE:
LCI = μ - (t-value * SE)
LCI = 11.48 - (2.262 * 0.0253)
LCI = 11.4228 ppm
The 95% upper confidence interval is the mean plus the product of the t-value and SE:
UCI = μ + (t-value * SE)
UCI = 11.48 + (2.262 * 0.0253)
UCI = 11.5372 ppm
A researcher is interested in developing a model that can be used to distribute assistance to low-income families for food costs. She used data from a national social survey to predict weekly amount spent on food using household income (in $1000). The resulting regression equation is ModifyingAbove Food divided by wk with caret equals 101.33 plus 0.77 HIncome.Food/wk=101.33+0.77HIncome. How much money would be needed to feed a family for a week whose household income is $12,000?
The estimated cost to feed a family for a week with a household income of $12,000 would be $9,341.33.
Explanation:To find out how much money would be needed to feed a family for a week whose household income is $12,000, we need to use the regression equation provided. The equation is Food/wk = 101.33 + 0.77HIncome. We substitute the value of HIncome with $12,000 and solve for Food/wk.
Food/wk = 101.33 + 0.77(12,000)
Food/wk = 101.33 + 9240
Food/wk = $9,341.33
Therefore, the estimated cost to feed a family for a week with a household income of $12,000 would be $9,341.33.
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