Question 21 of 400.0/ 2.5 Points

 

Which point below would be an outlier if it were on the following graph?

 

 

 

A. (25, 20)

 

 

 

B. (5, 12)

 

 

 

C. (7, 5)

 

 

 

D. (5, 3)

 

 

 

Question 22 of 400.0/ 2.5 Points

 

Among a random sample of 500 college students, the mean number of hours worked per week at non-college related jobs is 14.6. This mean lies 0.4 standard deviations below the mean of the sampling distribution. If a second sample of 500 students is selected, what is the probability that for the second sample, the mean number of hours worked will be less than 14.6?

 

 

 

A. 0.5

 

 

 

B. 0.6179

 

 

 

C. 0.6554

 

 

 

D. 0.3446

 

 

 

Question 23 of 400.0/ 2.5 Points

 

The scatter plot and best-fit line show the relation among the number of cars waiting by a school (y) and the amount of time after the end of classes (x) in arbitrary units. The correlation coefficient is -0.55. Determine the amount of variation in the number of cars not explained by the variation time after school.

 

 

 

A. 55%

 

 

 

B. 70%

 

 

 

C. 30%

 

 

 

D. 45%

 

 

 

Question 24 of 400.0/ 2.5 Points

 

Among a random sample of 150 employees of a particular company, the mean commute distance is 29.6 miles. This mean lies 1.2 standard deviations above the mean of the sampling distribution. If a second sample of 150 employees is selected, what is the probability that for the second sample, the mean commute distance will be less than 29.6 miles?

 

 

 

A. 0.8849

 

 

 

B. 0.5

 

 

 

C. 0.1131

 

 

 

D. 0.1151

 

 

 

Question 25 of 400.0/ 2.5 Points

 

A researcher wishes to estimate the proportion of college students who cheat on exams. A poll of 560 college students showed that 27% of them had, or intended to, cheat on examinations. Find the 95% confidence interval.

 

 

 

A. 0.2323 to 0.3075

 

 

 

B. 0.2325 to 0.3075

 

 

 

C. 0.2325 to 0.3185

 

 

 

D. 0.2323 to 0.3185

 

 

 

Question 26 of 400.0/ 2.5 Points

 

Which line of the three shown in the scatter diagram below fits the data best?

 

 

 

A. A

 

 

 

B. B

 

 

 

C. C

 

 

 

D. All the lines are equally good

 

 

 

Question 27 of 400.0/ 2.5 Points

 

Which graph has two groups of data, correlations within each group, but no correlation among all the data?

 

 

 

A.

 

 

 

B.

 

 

 

C.

 

 

 

D.

 

 

 

Question 28 of 400.0/ 2.5 Points

 

A researcher wishes to estimate the mean amount of money spent per month on food by households in a certain neighborhood. She desires a margin of error of $30. Past studies suggest that a population standard deviation of $248 is reasonable. Estimate the minimum sample size needed to estimate the population mean with the stated accuracy.

 

 

 

A. 274

 

 

 

B. 284

 

 

 

C. 264

 

 

 

D. 272

 

 

 

Question 29 of 400.0/ 2.5 Points

 

Select the best fit line on the scatter diagram below.

 

 

 

A. A

 

 

 

B. B

 

 

 

C. C

 

 

 

D. All of the lines are equally good

 

 

 

Question 30 of 400.0/ 2.5 Points

 

Select the best fit line on the scatter diagram below.

 

 

 

A. A

 

 

 

B. B

 

 

 

C. C

 

 

 

D. None of the lines is the line of best fit

 

 

 

Question 31 of 400.0/ 2.5 Points

 

A random sample of 30 households was selected from a particular neighborhood. The number of cars for each household is shown below. Estimate the mean number of cars per household for the population of households in this neighborhood. Give the 95% confidence interval.

 

 

 

A. 1.14 to 1.88

 

 

 

B. 1.12 to 1.88

 

 

 

C. 1.12 to 1.98

 

 

 

D. 1.14 to 1.98

 

 

 

Question 32 of 400.0/ 2.5 Points

 

The graph shows a measure of fitness (y) and miles walked weekly. Identify the probable cause of the correlation.

 

 

 

A. The correlation is coincidental.

 

 

 

B. There is a common underlying cause of the correlation.

 

 

 

C. There is no correlation between the variables.

 

 

 

D. Walking is a direct cause of the fitness.

 

 

 

Question 33 of 400.0/ 2.5 Points

 

Monthly incomes of employees at a particular company have a mean of $5954. The distribution of sample means for samples of size 70 is normal with a mean of $5954 and a standard deviation of $259. Suppose you take a sample of size 70 employees from the company and find that their mean monthly income is $5747. How many standard deviations is the sample mean from the mean of the sampling distribution?

 

 

 

A. 0.8 standard deviations above the mean

 

 

 

B. 0.8 standard deviations below the mean

 

 

 

C. 7.3 standard deviations below the mean

 

 

 

D. 207 standard deviations below the mean

 

 

 

Question 34 of 400.0/ 2.5 Points

 

Suggest the cause of the correlation among the data.

 

The graph shows strength of coffee (y) and number of scoops used to make 10 cups of coffee (x). Identify the probable cause of the correlation.

 

 

 

 

 

A.

 

The variation in the x variable is a direct cause of the variation in

the y variable.

 

 

 

B. There is no correlation between the variables.

 

 

 

C. The correlation is due to a common underlying cause.

 

 

 

D. The correlation between the variables is coincidental.

 

 

 

Question 35 of 400.0/ 2.5 Points

 

A sample of 64 statistics students at a small college had a mean mathematics ACT score of 28 with a standard deviation of 4. Estimate the mean mathematics ACT score for all statistics students at this college. Give the 95% confidence interval.

 

 

 

A. 28.0 to 30.0

 

 

 

B. 25.0 to 27.0

 

 

 

C. 29.0 to 31.0

 

 

 

D. 27.0 to 29.0

 

 

 

Question 36 of 400.0/ 2.5 Points

 

30% of the fifth grade students in a large school district read below grade level. The distribution of sample proportions of samples of 100 students from this population is normal with a mean of 0.30 and a standard deviation of 0.045. Suppose that you select a sample of 100 fifth grade students from this district and find that the proportion that reads below grade level in the sample is 0.36. What is the probability that a second sample would be selected with a proportion less than 0.36?

 

 

 

A. 0.8932

 

 

 

B. 0.8920

 

 

 

C. 0.9032

 

 

 

D. 0.9048

 

 

 

Question 37 of 400.0/ 2.5 Points

 

Of the 6796 students in one school district, 1537 cannot read up to grade level. Among a sample of 812 of the students from this school district, 211 cannot read up to grade level. Find the sample proportion of students who cannot read up to grade level.

 

 

 

A. 0.14

 

 

 

B. 0.26

 

 

 

C. 211

 

 

 

D. 0.23

 

 

 

Question 38 of 400.0/ 2.5 Points

 

A population proportion is to be estimated. Estimate the minimum sample size needed to achieve a margin of error E = 0.01with a 95% degree of confidence.

 

 

 

A. 7,000

 

 

 

B. 8,000

 

 

 

C. 9,000

 

 

 

D. 10,000

 

 

 

Question 39 of 400.0/ 2.5 Points

 

The scatter plot and best-fit line show the relation between the price per item (y) and the availability of that item (x) in arbitrary units. The correlation coefficient is -0.95. Determine the amount of variation in pricing explained by the variation in availability.

 

 

 

A. 5%

 

 

 

B. 10%

 

 

 

C. 95%

 

 

 

D. 90%

 

 

 

Question 40 of 400.0/ 2.5 Points

 

In a poll of 400 voters in a certain state, 61% said that they opposed a voter ID bill that might hinder some legitimate voters from voting. The margin of error in the poll was reported as 4 percentage points (with a 95% degree of confidence). Which statement is correct?

 

 

 

A. The reported margin of error is consistent with the sample size.

 

 

 

B. There is not enough information to determine whether the margin of error is consistent with the sample size.

 

 

 

C. The sample size is too small to achieve the stated margin of error.

 

 

 

D. For the given sample size, the margin of error should be smaller than stated.