Reference no: EM132233897

Statistics Questions -

Q1. A human resources manager wants to determine a confidence interval estimate for the mean test score for the next office-skills test to be given to a group of job applicants. In the past, the test scores have been normally distributed with a mean of 74.2 and a standard deviation of 30.9. Determine a 95% confidence interval estimate if there are 30 applicants in the group.

A. 64.92 to 83.48

B. 13.64 to 134.76

C. 63.14 to 85.26

D. 68.72 to 79.68

Q2. An online auction website allows sellers to place a reserve on their items up for auction. Bids on an item with a reserve must exceed a predetermined price before the seller commits to the transaction. In a sample of 2,617 auctions, the mean reserve was $112 with a standard deviation of $560. Find an approximate 95% confidence interval for the true mean reserve price, µ.

A. 116 ± 18.46

B. 112 ± 25.56

C. 112 ± 21.46

D. 110 ± 20.61

Q3. Using a sample size of n = 400. If σ = 20 and x = 72.5, find the value of the test statistic. Consider the test H₀ : μ = 70 versus H_α : μ > 70.

A. 2.3

B. 2.5

C. 1.8

D. 2.25

Q4. Determine which of the following four population size and sample size combinations would not require the use of the finite population correction factor in calculating the standard error.

A. N = 1500; n = 300

B. N = 15,000; n = 1,000

C. N = 150; n = 25

D. N = 2500; n = 75

Q5. Researchers conduct an online survey of American adults to determine their favorite sport. About 90% of American adults consider themselves sports fans. You believe that professional football will be determined to be the favorite sport for 40% of American adults. Professional football brings in 36% of all annual revenue for ads for televised events. Specify the null and alternative hypothesis for your belief that professional football is the favorite sport of American adults.

A. H₀ : p = .6, H_α : p ≠ .6

B. H₀ : p = .36, H_α : p ≠ .36

C. H₀ : p = .9, H_α : p ≠ .9

D. H₀ : p = .4, H_α : p ≠ .4

Q6. In a simple random sample from a population of several hundred that's approximately normally distributed, the following data values were collected: 68, 79, 70, 98, 74, 79, 50, 102, 92, 96

Based on this information, the confidence level would be 90% that the population mean is somewhere between

A. 69.15 and 92.45.

B. 73.36 and 88.24.

C. 71.36 and 90.24.

D. 65.33 and 95.33.

Q7. In the statement of a null hypothesis, you would likely find which of the following terms?

A. =

B. <

C. >

D. +

Q8. Find z_α/2 when α = .01.

A. 1.96

B. 2.576

C. 1.645

D. 1.282

Q9. With larger and larger numbers of categories in chi-square tests, the chi-square distribution takes on the shape of the _______ distribution.

A. t-

B. normal

C. Poisson

D. binomial

Q10. Consider a null hypothesis stating that the population mean is equal to 52, with the research hypothesis that the population mean isn't equal to 52. Assume you've collected 38 sample data from which we computed a sample mean of 53.67 and a sample standard deviation of 3.84. Further assume the sample data appear approximately normal. What's the p-value you would report for this test?

A. 0.0041

B. 0.0074

C. 0.0084

D. 0.0025

Q11. The average length of stay at a popular hotel chain is 4.5 days. A random sample of 20 hotels in the chain had a mean length of stay of 3.8 days and a standard deviation of 1.2 days. Estimate μ, the mean length of stay at all hotels in the chain, with 90% confidence.

A. 3.9 ± .645

B. 2.8 ± .664

C. 3.2 ± .464

D. 3.8 ± .464

Q12. A company that develops artificial intelligence designed to detect false statements has developed a program that police officers can use to determine whether a criminal suspect is lying or not. According to the company, the AI can detect false statements correctly 75% of the time. What are the null and alternative hypothesis for testing the claim that the AI detects false statements as claimed by the company?

A. H₀ : p = .99, H_α : p ≠ .99

B. H₀ : p = .25, H_α : p ≠ .25

C. H₀ : p = .01, H_α : p ≠ .01

D. H₀ : p = .75, H_α : p ≠ .75

Q13. If a teacher wants to test her belief that more than five students in college classes typically receive A as a grade, she'll perform _______-tail testing of a mean.

A. one

B. left

C. two

D. right

Q14. Find the p-value of the test H₀ : μ 100 when H_α0 : μ ≠ 100 and z = 2.17.

A. .015

B. .025

C. .030

D. .033

Q15. Find z_α/2 when α = .10

A. 1.282

B. 1.96

C. 2.576

D. 1.645

Q16. In sampling without replacement from a population of 900, it's found that the standard error of the mean, σ_x, is only two-thirds as large as it would have been if the population were infinite in size. What's the approximate sample size?

A. 200

B. 400

C. 600

D. 500

Q17. Which element of a test of a hypothesis is used to decide whether to reject the null hypothesis in favor of the alternative hypothesis?

A. Rejection region

B. Conclusion

C. Test statistic

D. Level of significance

Q18. Nondirectional assertions lead only to _______-tail tests.

A. left

B. two

C. one

D. right

Q19. Find the p-value of the test H₀ : μ = 7 when H_α : μ > 7 and z = 120.

A. .1151

B. .2302

C. .1365

D. .1620

Q20. Assuming N = 10,000, n = 4,000, and s = 50, compute the standard error of x using the finite population correction factor.

A. .6124

B. .6024

C. .6358

D. .5931