10 Questions
| Total Attempts: 55967

Questions and Answers

- 1.Estimate the critical value of t for a 98% confidence interval with df = 20
- A.
2.528

- B.
2.518

- C.
1.325

- D.
2.539

- E.
2.330

- 2.Find the P-value for |t| > 1.76 with 24 degrees of freedom.
- A.
.0911

- B.
.0456

- C.
.1562

- D.
.9544

- E.
.0781

- 3.You want to estimate the average gas price in your city for a gallon of regular gas. From your sample of 15 gas stations, you calculate a 95% confidence interval of ($1.98, $2.16). Interpret the confidence interval.
- A.
You are 95% sure that the average price for a gallon of gas in your city is between $1.98 and $2.16.

- B.
If you took many samples of gas stations in your city, about 95% of them would produce this confidence interval.

- C.
95% of all samples of gas stations will have average costs between $1.98 and $2.16.

- D.
You are 95% sure that gas stations in this sample have average costs between $1.98 and $2.16.

- E.
You are 95% confident that the average price for a gallon of gas in the country is within $0.09 of $2.07.

- 4.
**A confidence interval estimate is determined from the**GPAs of a simple random sample of*n*students. All other things being equal, which of the following will result in a smaller margin of error?- A.
A smaller confidence level

- B.
A larger sample standard deviation

- C.
A smaller sample size

- D.
A larger population size

- E.
A smaller sample mean

- 5.
**In an SRS of 80 teenagers, the average number of texts handled in a day was 50 with a standard deviation of 15. What is the 96% confidence interval for the average number of texts handled by teens daily?**- A.
- B.
- C.
- D.
- E.

- 6.
**The number of accidents per day at a large factory is noted for each of 64 days with a mean of 3.58 and a standard deviation of 1.52. With that degree of confidence, we can assert that the mean number of accidents per day at the factory is between 3.20 and 3.96.**- A.
95%

- B.
48%

- C.
63%

- D.
90%

- E.
99%

- 7.Two confidence interval estimates are obtained: I (28.5, 34.5) and II (30.3, 38.2).
- If the sample sizes are the same, which has a larger standard deviation?
- If the sample standard deviations are the same, which has a larger size?

- A.
1. I 2. II

- B.
1. I 2. I

- C.
1. II 2. I

- D.
1. II 2. II

- E.
More information is needed to answer these questions

- 8.
**A company selling home appliances claims that the accompanying instruction manuals are written at a 6th-grade reading level. An English teacher believes that the true figure is higher and with the help of an AP Stat student runs a hypothesis test. The student randomly picks one page from each of 25 of the company's instructions manuals, and the teacher subjects the pages to a standard readability test. The reading levels of the 25 pages are given in the following table:**Reading Grade Level 5 6 7 8 9 10 Number of pages 6 10 4 2 2 1**Is there statistical evidence to support the English teacher's belief?**- A.
No, because the p-value is greater than .10

- B.
Yes, the p-value is between .01 and .05 indicating some evidence for the teacher's belief.

- C.
Yes, the p-value is between .001 and .01 indicating strong evidence for the teacher's belief.

- D.
Yes, the p-value is between .05 and .10 indicating strong evidence for the teacher's belief.

- E.
Yes, the p-value is less than .001 indicating strong evidence for the teacher's belief.

- 9.
**Thirty students volunteer to test which of two strategies for taking multiple-choice exams leads to higher average results. Each student flips a coin, and if heads, uses Strategy A on the first exam and then Strategy B on the second exam, while if tails, uses Strategy B first and then Strategy A. The average of all 30 Strategy A result is then compared to the average of all 30 Strategy B results. What is the conclusion at the 5% significance level if a two-sample hypothesis test, , results in a p-value of .18?**- A.
The observed difference in average scores is significant.

- B.
The observed difference in average scores is not significant.

- C.
A conclusion is not possible without knowing the average scores resulting from using each strategy.

- D.
A conclusion is not possible without knowing the averages scores and the standard deviations resulting from using each strategy.

- E.
A two-sample hypothesis test should not be used here.

- 10.Based on data from two very large independent samples, two students tested a hypothesis about equality of population means using α = 0.02. One student used a one-tail test and rejected the null hypothesis, but the other used a two-tail test and failed to reject the null. Which of these might have been their calculated value of t?
- A.
1.55

- B.
1.22

- C.
2.22

- D.
1.88

- E.
2.66