Several years ago, 38% of parents who had children in grades K-12 were satisfied with the quality of education the students receive. A recent poll asked 1 comma 165 parents who have children in grades K-12 if they were satisfied with the quality of education the students receive. Of the 1 comma 165 surveyed, 499 indicated that they were satisfied. Construct a 95% confidence interval to assess whether this represents evidence that parents' attitudes toward the quality of education have changed.
Answer:
[tex]0.428 - 1.96\sqrt{\frac{0.428(1-0.428)}{1165}}=0.3995[/tex]
[tex]0.428 + 1.96\sqrt{\frac{0.428(1-0.428)}{1165}}=0.4564[/tex]
We are confident that the true proportion of people satisfied with the quality of education the students receive is between (0.3995, 0.4564), since the lower value for this confidence level is higher than 0.38 we have enough evidence to conclude that the parents' attitudes toward the quality of education have changed.
Step-by-step explanation:
For this case we are interesting in the parameter of the true proportion of people satisfied with the quality of education the students receive
The confidence level is given 95%, the significance level would be given by [tex]\alpha=1-0.95=0.05[/tex] and [tex]\alpha/2 =0.025[/tex]. And the critical values are:
[tex]z_{\alpha/2}=-1.96, z_{1-\alpha/2}=1.96[/tex]
The estimated proportion of people satisfied with the quality of education the students receive is given by:
[tex]\hat p =\frac{499}{1165}= 0.428[/tex]
The confidence interval for the proportion if interest is given by the following formula:
[tex]\hat p \pm z_{\alpha/2}\sqrt{\frac{\hat p (1-\hat p)}{n}}[/tex]
And replacing the info given we got:
[tex]0.428 - 1.96\sqrt{\frac{0.428(1-0.428)}{1165}}=0.3995[/tex]
[tex]0.428 + 1.96\sqrt{\frac{0.428(1-0.428)}{1165}}=0.4564[/tex]
We are confident that the true proportion of people satisfied with the quality of education the students receive is between (0.3995, 0.4564), since the lower value for this confidence level is higher than 0.38 we have enough evidence to conclude that the parents' attitudes toward the quality of education have changed.
Charlie is driving to Boston. Suppose that the distance to his destination (in miles) is a linear function of his total driving time (in minutes). Charlie has 49 miles to his destination after 15 minutes of driving, and he has 32.2 miles to his destination after 39 minutes of driving. How many miles will he have to his destination after 47 minutes of driving
Answer:26.6 miles
Step-by-step explanation:
Given
Charlie distance to his destination is a linear function of total driving time
suppose distance d is related to time t as
[tex]d=mt+c\quad \ldots(i)[/tex]
at [tex]d=49\ miles[/tex] after [tex]t=15\ min[/tex]
Substitute in (i)
[tex]49=m(15)+c\quad \ldots(ii)[/tex]
at [tex]d=32.2\ miles[/tex] after [tex]t=39\ min[/tex]
[tex]32.2=m(39)+c\quad \ldots(iii)[/tex]
Solving (ii) and (iii) we get
[tex]m=-0.7[/tex]
substitute in eq (ii) we get
[tex]c=59.5[/tex]
so after [tex]t=47\ min[/tex]
[tex]d=(-0.7)47+59.5[/tex]
[tex]d=59.5-32.9=26.6\ miles[/tex]
So 26.6 miles is left to travel after 47 minutes
A spherical boulder is 18 ft in diameter and weighs almost 8 tons. Find the volume. Use 3.14 for piπ.
The volume of a spherical boulder with a diameter of 18 ft can be calculated using the formula V = 4/3πr³, with 'r' being the radius of the sphere. By substituting the radius of 9 ft (half of 18 ft), we find that the volume is approximately 3053.62 cubic feet.
Explanation:To find the volume of a sphere, we use the formula: V = 4/3πr³, where 'r' is the radius of the sphere. The radius can be found from the diameter by dividing it by 2; therefore, for this boulder, the radius will be 18 ft/2 = 9 ft. Substituting 'r' into the volume equation: V = 4/3 * 3.14 * (9ft)³ = 3053.62 cubic feet. Therefore, the spherical boulder has a volume of approximately 3053.62 cubic feet.
To find the volume of a spherical boulder, we can use the formula for the volume of a sphere, which is V = (4/3)πr³. Given that the diameter of the boulder is 18 ft, we can find the radius by dividing the diameter by 2, which gives us a radius of 9 ft. Plugging this value into the formula, we get V = (4/3)π(9 ft)³. Using the value of π as 3.14, we can calculate the volume:
V = (4/3)(3.14)(9 ft)³ = (4/3)(3.14)(729 ft³) = 3053.96 ft³
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The weekly earnings of students in one age group are normally distributed with a standard deviation of 10 dollars. A researcher wishes to estimate the mean weekly earnings of students in this age group. Find the sample size needed to assure with 95 percent confidence that the sample mean will not differ from the population mean by more than 2 dollars.
Answer:
We need a sample size of at least 97.
Step-by-step explanation:
We have that to find our [tex]\alpha[/tex] level, that is the subtraction of 1 by the confidence interval divided by 2. So:
[tex]\alpha = \frac{1-0.95}{2} = 0.025[/tex]
Now, we have to find z in the Ztable as such z has a pvalue of [tex]1-\alpha[/tex].
So it is z with a pvalue of [tex]1-0.025 = 0.975[/tex], so [tex]z = 1.96[/tex]
Now, find the margin of error M as such
[tex]M = z*\frac{\sigma}{\sqrt{n}}[/tex]
In which [tex]\sigma[/tex] is the standard deviation of the population and n is the size of the sample.
Find the sample size needed to assure with 95 percent confidence that the sample mean will not differ from the population mean by more than 2 dollars.
We need a sample size of at least n.
n is found when [tex]M = 2, \sigma = 10[/tex].
So
[tex]M = z*\frac{\sigma}{\sqrt{n}}[/tex]
[tex]2 = 1.96*\frac{10}{\sqrt{n}}[/tex]
[tex]2\sqrt{n} = 1.96*10[/tex]
[tex]\sqrt{n} = \frac{1.96*10}{2}[/tex]
[tex](\sqrt{n})^{2} = (\frac{1.96*10}{2})^{2}[/tex]
[tex]n = 96.04[/tex]
Rouding up
We need a sample size of at least 97.
A 4-story office building has cubicles for 348plus313plus306plus308 workers. While one floor is closed for repairs, the office has cubicles for 348plus306plus308 workers. How many cubicles are there on the floor that is closed? Explain.
Answer:
313
Step-by-step explanation:
We observe that the numbers of cubicles on the open floors have not changed, so we can match the numbers to find the missing one.
The closed floor has 313 cubicles.
To find the number of cubicles on the closed floor, one must subtract the total number of cubicles available when one floor is closed from the original total of all floors. The closed floor has 313 cubicles.
The question asked is about determining the number of cubicles on a floor that is closed for repairs in a 4-story office building. Initially, the building has cubicles for 348 + 313 + 306 + 308 workers. When one floor is closed, it has cubicles for 348 + 306 + 308 workers. To find the number of cubicles on the closed floor, we subtract the total number of cubicles available while the floor is closed from the original total when all floors were open.
The calculation would be as follows:
Total number of cubicles when all floors are open = 348 + 313 + 306 + 308Total number of cubicles with one floor closed = 348 + 306 + 308Cubicles on the closed floor = (Total number of cubicles when all floors are open) - (Total number of cubicles with one floor closed)Step-by-step calculation:
First, calculate the total when all floors are open: 348 + 313 + 306 + 308 = 1275 cubicles.Then, calculate the total with one floor closed: 348 + 306 + 308 = 962 cubicles.Finally, subtract to find the number on the closed floor: 1275 - 962 = 313 cubicles.Therefore, there are 313 cubicles on the floor that is closed.
The effect of drugs and alcohol on the nervous system has been the subject of considerable research recently. Suppose a research neurologist is testing the effect of a drug on response time by injecting 150 rats with a unit of dose of the drug, subjecting each to neurological stimulus, and recording its response time. The neurologist knows that the mean response time for rats not injected with the drug (the "control" mean) is 1.2 seconds. S/he wishes to test whether the mean response time for the drug-injected rats is greater than 1.2 seconds. If the sampling experiment is conducted with the sample mean equal to 1.05 second, set up the test of hypothesis for this experiment and determine if the results are significant. Suppose drug-injected rats have a mean response time of 1.1 .seconds, that is mu = 1.1 seconds.
Calculate the value of beta corresponding to the two rejection regions.
The student's question involves a statistical hypothesis test to compare the mean response times between drug-injected and control rats. The calculation of beta, representing the risk of Type II error, requires more information not provided in the question.
Explanation:The given scenario involves setting up a hypothesis test to determine if the mean response time for drug-injected rats is significantly different from the control group (rats not injected with the drug) with a known mean response time of 1.2 seconds. The null hypothesis would state that the mean response time for drug-injected rats (μ) is equal to 1.2 seconds (H0: μ = 1.2), while the alternative hypothesis would state that the mean response time is greater than 1.2 seconds (Ha: μ > 1.2).
Given that the sample mean response time for drug-injected rats is 1.05 seconds, which is actually lower than the control mean, this initially suggests that the drug does not increase the response time but rather decreases it or has no effect. However, as the question indicates a confusion with the typo in sample mean, we will proceed with testing the hypothesis based on the provided assumption that the drug-injected rats have a mean response time of 1.1 seconds.
To calculate the value of beta (the probability of a Type II error, which occurs when the null hypothesis is not rejected even though it is false), we would need to define the rejection regions for our test. The rejection region is typically defined based on the significance level (alpha) and the distribution of the test statistic under the null hypothesis. Without specifics such as the sample size, standard deviation, and significance level for defining the rejection regions, we cannot calculate beta directly.
Rafaela is a physical education teacher and has 252525 girls and 353535 boys in her class.
She wants to divide the class into teams of the same size, where each team has the same number of girls and the same number of boys.
If Rafaela creates the greatest number of teams possible, how many boys will be on each team?
Answer:
7 boys
Step-by-step explanation:
252525=3*5²*7*13*37
353535=3*5*7²*13*37
(252525; 353535)= 3 * 5 * 7 * 13 * 37 = 50505
The greatest number of teams possible=50505
252525=5*50505
353535=7*50505
So, are 50505 teams, each containing 5 girls and 7 boys.
7 boys
how many gallons of paint are needed to paint one coat, if a gallon of paint covers 400ft squared?
Answer:
6.28 gallons
Step-by-step explanation:
first we need to find the area of a half sphere, and then find how much paint will be needed for that area.
The area of a sphere:
[tex]a=4 \pi r^2[/tex]
thus, the area of half a sphere is:
[tex]a=2 \pi r^2[/tex]
we know that the radius is:
[tex]r=20ft[/tex]
we substitute this to find the area of the half sphere (the area they need to paint):
[tex]a=2\pi (20ft)^2\\a=2(3.1416) (400ft^2)\\a=2,513.27ft^2[/tex]
now the question is how many gallons of paint are needed to paint 2,513.27 square feet.
We are told that 1 gallon covers 400 square feet
thus, we must divide 2,513.27 by 400:
[tex]\frac{2,513.27ft^2}{400ft^2} =6.28[/tex]
6.28 gallons of paint are needed.
For a hypothesis test of H0 : μ = 8 vs. H0 : μ > 8, the sample mean of the data is computed to be 8.24. The population standard deviation is unknown; the sample standard deviation is computed, and its value is 0.29. These sample statistics are based on a sample size of 19. It is assumed that the underlying population is normally distributed. Which of the following would be the distribution of the test statistic in this scenario?a) The t-distribution with 8 degrees of freedomb) The standard normal distributionc) The t-distribution with 19 degrees of freedomd) The t-distribution with 18 degrees of freedom
Answer:
d) The t-distribution with 18 degrees of freedom
Step-by-step explanation:
If we have the population standard deviation, we use the standard normal distribution.
Otherwise, if we only have the standard deviation for the sample, we use the t-distribution.
The number of degrees of freedom is the sample size subtracted by 1.
In this problem:
Sample size of 19, we have the standard deviation for the sample.
So the t-distribution will be used to solve this question, with 19-1 = 18 degrees of freedom.
So the correct answer is:
d) The t-distribution with 18 degrees of freedom
In a hypothesis test where the population standard deviation is unknown and estimated by the sample standard deviation, we use the t-distribution with degrees of freedom equal to the sample size minus one. In this case, the distribution of the test statistic would follow a t-distribution with 18 degrees of freedom.
Explanation:In this particular case, the sample size is 19, and the population standard deviation is unknown and estimated by the sample standard deviation. Because of these conditions, the t-distribution would be used to determine the test statistic. Specifically, we would use the t-distribution with degrees of freedom equaling the sample size minus one, i.e., 18. Therefore, the correct answer among the options given is 'The t-distribution with 18 degrees of freedom'.
For example, suppose we have a set of samples from an unknown population, we compute the sample standard deviation and use it as an estimator of the actual unknown population standard deviation. In such cases, we use the t-distribution with (n-1) degrees of freedom, where n is our sample size. Here, it would be the t-distribution with 18 degrees of freedom because our sample size is 19.
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The college hiking club is having a fund raiser to buy new equipment for fall and winter outings. The club is selling Chinese fortune cookies at a price of $3 per cookie. Each cookie contains a piece of paper with a different number written on it. A random drawing will determine which number is the winner of a dinner for two at a local Chinese restaurant. The dinner is valued at $35. Since fortune cookies are donated to the club, we can ignore the cost of the cookies. The club sold 717 cookies before the drawing. Lisa bought 31 cookies. What is the probability she will win the dinner for two? Write your answer as a fraction in simplest form, if one exists.
Answer:
Check the explanation
Step-by-step explanation:
Kindly check the attached images below to see the step by step explanation to the question above.
if h is positive how does the parabola's move?
Answer:
it would move upwards.
Step-by-step explanation:
there is no such thing as a negative exponent because, if you were suppose to graph that you have the parabola go up and down, and that is not how it works.
A cone with height 12 centimeters and volume 16 pi centimeters cubed. What is the radius of the cone? 1 cm 2 cm 4 cm 8 cm
Answer:
2
Step-by-step explanation:
Answer:
2
Step-by-step explanation:
Took the assignment
The function f(x)=-(x-3)^2+9 can be used to represent the area of a rectangle with a perimeter of 12 units, as a function of the length of the rectangle, x. What is the maximum area of the rectangle?
Answer:
9.
Step-by-step explanation:
[tex]f(x) = -(x - 3)^2 + 9[/tex] is a parabola in its vertex form. For clarity, let [tex]f(x) = a (x - h)^2 + k[/tex] represent this function.
[tex]a = -1[/tex].[tex]h = 3[/tex].[tex]k = 9[/tex].Note that [tex]a[/tex], the leading coefficient, is negative. Therefore, this parabola opens downwards. The vertex of the parabola would be [tex](h,\, k)[/tex], which in this question is the point [tex](3,\, 9)[/tex]. Since the parabola opens downwards, that vertex would be a local maximum (a crest) on its graph.
Before concluding that the maximum area of this rectangle is [tex]9[/tex], make sure that [tex](3,\, 9)[/tex] is indeed on the graph of [tex]y = f(x)[/tex].
The length of a rectangle should be positive. Since [tex]x[/tex] represents the length of this rectangle, [tex]x > 0[/tex]. Also, since the perimeter should be less than [tex]12[/tex], the length of one side should be less than [tex]12 / 2 = 6[/tex]. Therefore, the domain of [tex]f[/tex] should be the open interval [tex](0,\, 6)[/tex]. (Endpoints not included.)
Indeed, [tex]x = 3[/tex] is in that interval. [tex](3,\, 9)[/tex] would be on the graph [tex]y = f(x)[/tex]. Therefore, [tex]9[/tex] is indeed the maximum area of this rectangle.
Side note: if the domain is a closed interval (i.e., endpoints included,) then consider checking the endpoints, as well.
Answer:
Step-by-step explanation:
9
How do you solve this?
A spinner with the colors red, blue, yellow, green, and orange is spun. What is the theoretical probability of landing on orange?
The theoretical probability of landing on orange when spinning a spinner with five colors is 1/5.
Since there are five colors on the spinner, each color has an equal chance of landing, so the theoretical probability of landing on orange is 1 out of 5, or 1/5.
The rectangle has an area of 198 square millimeters. The length is 9 millimeters. What is the width of the rectangle?
Answer:
22 millimetres
Step-by-step explanation:
[tex]width \: of \: rectangle \\ = \frac{area}{length} \\ = \frac{198}{9} \\ = 22 \: millimeters \\ [/tex]
Twelve synchronized swimmers are forming a circle. The locations of three of those swimmers are (13,-2),(-1,-2),and (6,-9). A 4th swimmer will appear in the middle of the circle. Where would the center swimmer need to be located?
Answer:(6,-2)
Step-by-step explanation:
The center swimmer need to be located at the point (6, -2).
What is the Standard form of a Circle?Standard form of a circle is given by the equation,
(x - h)² + (y - k)² = r²
where, (h, k) is the center of the circle and r is the radius of the circle.
Given are three points on a circle.
(13, -2), (-1, -2) and (6, -9).
Substituting each of the point in the standard form,
(13 - h)² + (-2 - k)² = r²
(-1 - h)² + (-2 - k)² = r²
(6 - h)² + (-9 - k)² = r²
Since the radius are equal,
(13 - h)² + (-2 - k)² = (-1 - h)² + (-2 - k)² = (6 - h)² + (-9 - k)²
Solving the first two equations, we get,
(13 - h)² = (-1 - h)²
28h = 168
h = 6
From the last two equations,
(-1 - h)² + (-2 - k)² = (6 - h)² + (-9 - k)²
49 + (-2 - k)² = (-9 - k)²
k = -2
Hence the center of the circle is (h, k) = (6, -2).
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Write the equation of the line that is parallel to y = -2x - 9 and passes through the point (-2,-4).
Answer: y=-2x-8
Step-by-step explanation:
Parallel lines need to have the same slopes but different y-intercept.
y=-2x -9 is parallel to y=-2x - 8
A market researcher for Eric’s Electronics wants to study TV viewing habits of residents in Chicago. The individuals in the survey are asked to keep track of their weekly TV viewing time. A random sample of 50 respondents is selected, and the average viewing time per week for the 50 individuals in the sample is 17.5 hours. The population standard deviation is known to be 5.0 hours. Assume that TV viewing is a normally distributed random variable. (7 points) Construct a 90% confidence interval estimate for the mean amount of television watched per week by individuals in Chicago. Interpret your result.
Answer:
Step-by-step explanation:
Confidence interval is written in the form,
(Sample mean - margin of error, sample mean + margin of error)
The sample mean, x is the point estimate for the population mean.
Since the sample size is large and the population standard deviation is known, we would use the following formula and determine the z score from the normal distribution table.
Margin of error = z × σ/√n
Where
σ = population standard Deviation
n = number of samples
From the information given
1) x = 17.5
σ = 5
n = 50
To determine the z score, we subtract the confidence level from 100% to get α
α = 1 - 0.9 = 0.1
α/2 = 0.1/2 = 0.05
This is the area in each tail. Since we want the area in the middle, it becomes
1 - 0.05 = 0.95
The z score corresponding to the area on the z table is 1.645. Thus, confidence level of 90% is 1.645
Margin of error = 1.645 × 5/√50 = 1.16
Confidence interval = 17.5 ± 1.16
Which opening sentence goes best with the details in the above paragraph?
A.
Recycling programs have become popular.
B.
Pollution from burning of fossil fuels causes acid rain.
C.
Canada is a land rich in mineral resources.
D.
The United States is rich in resources.
People have often acted as though these resources were unlimited. In recent years, however, the people of the United States have started to understand that they must use their resources more wisely than in the past.
Answer:
The United states is rich in resources
Step-by-step explanation:
Got it right on study island:))
Final answer:
The opening sentence that best fits the paragraph's context is 'The United States is rich in resources,' as it introduces the theme of resource consumption and sustainability within the U.S.
Explanation:
The best opening sentence that goes with the details in the paragraph provided is option D: The United States is rich in resources. This opening sentence sets the context for discussing how the people in the United States have historically acted as if their resources were unlimited. It leads into the realization that there must be a more prudent approach to using resources going forward, as indicated in the paragraph. The passage indicates a shift in understanding within the United States regarding resource consumption and the necessity for wiser use, aligning well with the recognition of resource richness and the implication of historical abundance.
The graph of y=h(x) is shown below. The function f(x) is defined by f(x) =-1/2h(x)+3. (a) What three transformations have occurred to the graph of h to produce the graph of f? Specify the transformations and the order they occurred in.
Answer:
Reflection over x, Stretch by 1/2, translate up 3 units
Step-by-step explanation:
:)
The graph of the function h(x) has undergone three transformations to produce the function f(x) = -1/2h(x) + 3: a reflection in the x-axis, a vertical scaling by 1/2, and a vertical shift upward by 3 units.
Explanation:The function f(x) = -1/2h(x) + 3 has gone through three transformations to become the graph of h(x), which are determined by applying different values of x and the corresponding values of y. Firstly, the graph h(x) is reflected in the x-axis due to the negative sign in front of the h(x), which reverses the direction of the graph. Secondly, the graph is scaled vertically by a factor of 1/2 due to the multiplication of h(x) by 1/2, which compresses the graph towards the x-axis. Lastly, the graph is translated vertically upwards by 3 units as a result of the +3 in the equation, shifting the entire graph upwards.
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For each 11 mm of coloured fabric Nick uses to make his curtains, he also uses 2 cm of white fabric. Express the amount of white fabric to coloured fabric as a ratio in its simplest form.
Answer:
The amount of white fabric to coloured fabric as a ratio is 20:11
Step-by-step explanation:
We are given that For each 11 mm of colored fabric Nick uses to make his curtains, he also uses 2 cm of white fabric.
Length of colored fabric = 11 mm
Length of White fabric = 2 cm
1 cm = 10 mm
2 cm = 20 mm
So, length of white fabric = 20 mm
So, Ratio of the amount of white fabric to coloured fabric = [tex]\frac{20}{11}[/tex]
Hence the amount of white fabric to coloured fabric as a ratio is 20:11
In a right triangle, which ratio represents the sine of an angle?
a.
StartFraction opposite Over hypotenuse EndFraction
c.
StartFraction opposite Over opposite Endfraction
b.
StartFraction adjacent Over hypotenuse EndFraction
d.
StartFraction opposite Over adjacent EndFraction
Please sele
Answer:
A
Step-by-step explanation:
A prisoner is trapped in a cell containing three doors. The first door leads to a tunnel that returns him to his cell after two days’ travel. The second leads to a tunnel that returns him to his cell after four days’ travel. The third door leads to freedom after one day of travel. If it is assumed that the prisoner will always select doors 1, 2, and 3 with respective probabilities 0.3, 0.5, and 0.2, what is the expected number of days until the prisoner reaches freedom?
The expected number of days until the prisoner reaches freedom is 2.8 days.
To find the expected number of days until the prisoner reaches freedom, we can use the concept of expected value. We'll multiply the number of days it takes to reach freedom through each door by the probability of choosing that door, and then sum up these values.
Let's denote:
[tex]- \( X_1 \)[/tex] as the number of days it takes to reach freedom through door 1 (returns to the cell after 2 days).
[tex]- \( X_2 \)[/tex] as the number of days it takes to reach freedom through door 2 (returns to the cell after 4 days).
[tex]- \( X_3 \)[/tex] as the number of days it takes to reach freedom through door 3 (direct freedom after 1 day).
Given the probabilities:
- Probability of choosing door 1: [tex]\( P(X_1) = 0.3 \)[/tex]
- Probability of choosing door 2: [tex]\( P(X_2) = 0.5 \)[/tex]
- Probability of choosing door 3: [tex]\( P(X_3) = 0.2 \)[/tex]
Now, we calculate the expected value:
[tex]\[ E[X] = P(X_1) \times X_1 + P(X_2) \times X_2 + P(X_3) \times X_3 \][/tex]
[tex]\[ E[X] = 0.3 \times 2 + 0.5 \times 4 + 0.2 \times 1 \][/tex]
[tex]\[ E[X] = 0.6 + 2 + 0.2 \][/tex]
[tex]\[ E[X] = 2.8 \][/tex]
So, the expected number of days until the prisoner reaches freedom is 2.8 days.
What is (x^2+3x-10)/(x-2)
The simplified expression is x+5.
To simplify the expression x^2 +3x−10 /x−2, you can use polynomial long division or factorization.
Here's how to do it by factorization:
Factor the numerator
x^2 +3x−10:
x^2 +3x−10=(x+5)(x−2)
Rewrite the expression with the factored form of the numerator:
(x+5)(x−2)/ x−2
Cancel out the common factor of x−2:
(x−2) /(x+5) /x−2
The simplified expression is x+5.
So, x^2 +3x−10/ x−2 =x+5.
find the solution set x^2+2x-8=0 separate the two answers with a comma
Answer:
-4, 2
Step-by-step explanation:
The equation can be factored as ...
(x +4)(x -2) = 0
This has solutions that make the factors zero:
x = -4, x = 2
The solution set is {-4, 2}.
In 1943, an organization surveyed 1100 adults and asked, "Are you a total abstainer from, or do you on occasion consume, alcoholic beverages?" Of the 1100 adults surveyed, 429 indicated that they were total abstainers. In a recent survey, the same question was asked of 1100 adults and 352 indicated that they were total abstainers. Has the proportion of adults who totally abstain from alcohol changed? Use the alphaequals0.10 level of significance.
Answer:
We conclude that the proportion of adults who totally abstain from alcohol has changed.
Step-by-step explanation:
We are given that in 1943, an organization surveyed 1100 adults and asked, "Are you a total abstainer from, or do you on occasion consume, alcoholic beverages?"
Of the 1100 adults surveyed, 429 indicated that they were total abstainers. In a recent survey, the same question was asked of 1100 adults and 352 in
Let p = proportion of adults who totally abstain from alcohol.
where, p = [tex]\frac{429}{1100}[/tex] = 0.39
So, Null Hypothesis, [tex]H_0[/tex] : p = 39% {means that the proportion of adults who totally abstain from alcohol has not changed}
Alternate Hypothesis, [tex]H_A[/tex] : p [tex]\neq[/tex] 39% {means that the proportion of adults who totally abstain from alcohol has changed}
The test statistics that would be used here One-sample z proportion statistics;
T.S. = [tex]\frac{\hat p-p}{\sqrt{\frac{\hat p(1-\hat p)}{n} } }[/tex] ~ N(0,1)
where, [tex]\hat p[/tex] = sample proportion of adults who totally abstain from alcohol = [tex]\frac{352}{1100}[/tex] = 0.32
n = sample of adults surveyed = 1100
So, test statistics = [tex]\frac{0.32-0.39}{\sqrt{\frac{0.32(1-0.32)}{1100} } }[/tex]
= -4.976
The value of z test statistics is -4.976.
Now, at 0.10 significance level the z table gives critical values of -1.645 and 1.645 for two-tailed test.
Since our test statistics doesn't lie within the range of critical values of z, so we have sufficient evidence to reject our null hypothesis as it will fall in the rejection region due to which we reject our null hypothesis.
Therefore, we conclude that the proportion of adults who totally abstain from alcohol has changed.
1
The slope of a vertical line is:
(a) o
(b) Undefined
R
(c) 1
(d) -1
Kelsey's car can go 120 miles on 4.8 gallons of gas.If her tank holds 18 gallons,how far can she travel on a full tank of fuel.
Answer: She can travel 450 miles with 18 gallons.
Step-by-step explanation:
[tex]\frac{4.8}{120}[/tex] = [tex]\frac{18}{x}[/tex] solve by cross product
4.8x = 2160
x= 450
Kelsey's car gets 25 miles per gallon, and with an 18-gallon tank, she can travel a total of 450 miles on a full tank.
Explanation:To calculate how far Kelsey can travel on a full tank of fuel, first we need to determine her car's fuel efficiency and then apply it to the full tank capacity. We are given that her car can travel 120 miles on 4.8 gallons of gas. This gives us a fuel efficiency rate we can use to find out the total distance she can travel on 18 gallons.
Step-by-step CalculationCalculate the miles per gallon (mpg) her car gets by dividing the total miles traveled by the gallons of gas used: 120 miles ÷ 4.8 gallons = 25 mpg.Calculate the total distance that can be traveled on a full 18-gallon tank by multiplying the fuel efficiency rate by the tank size: 25 mpg × 18 gallons = 450 miles.Therefore, Kelsey can travel 450 miles on a full tank of fuel.
Learn more about Fuel Efficiency Calculation here:https://brainly.com/question/28314501
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The table shows the results for spinning the spinner 75 times. What is the relative frequency for the event "spin a 3"?
Answer: 0.267
Step-by-step explanation:
The relative frequency is the number of times that we obtained a given outcome divided by the total numer of trials.
In this case we have 75 trials.
in 20 trials the outcome was a 3.
Then the relative frequency of the event "spin a 3" is:
p = 20/75 = 0.266... = 0.267
Answer:
look under the 3 and you get
20