8 Questions

Questions and Answers

- 1.Suppose we can reject the null hypothesis that u>=50 at the 5% significance level. Which of the following statements is definitely true?
- A.
We can reject the null hypothesis that u = 50 at the 5% significance level.

- B.
We can reject the null hypothesis that u>= 50 at the 10% significance level.

- C.
The value we obtained for t* was positive

- D.
The value we obtained for t* was greater than the critical value for an upper one-tailed hypothesis test at the 5% significance level.

- 2.Increasing the sample size used for a two-tailed hypothesis test will tend to:
- A.
Decrease the probability of a Type I error.

- B.
Decrease the probability of a Type II error.

- C.
Increase the probability of a Type I error.

- D.
Increase the probability of a Type II error.

- 3.Suppose that the 95% confidence interval for the population mean hours of studying per weekis (6.5; 6.9). Which of the following statements is true?
- A.
You would reject the null hypothesis that u>=6.5 at the 10% significance level

- B.
You would reject the null hypothesis that u

- C.
You would reject the null hypothesis that u=7.1 at the 5% significance level.

- D.
All of the above are true.

- 4.Which of the following would narrow the confidence interval for the population mean?
- A.
Decreasing the sample size.

- B.
Decreasing the significance level.

- C.
Both (a) and (b) would narrow the confidence interval

- D.
Neither (a) nor (b) would narrow the confidence interval.

- 5.The probability of a Type I error when doing a two-tailed hypothesis test at a 5% significance level is:
- A.
Equal to the probability of a Type I error when doing a one-tailed hypothesis test at a 2.5% significance level.

- B.
Equal to the probability of a Type I error when doing a one-tailed hypothesis test at a 5% significance level.

- C.
Equal to the probability of a Type I error when doing a one-tailed hypothesis test at a 10% significance level.

- D.
Equal to the probability of a Type I error when doing a one-tailed hypothesis test at a 20% significance level.

- 6.Which of the following would increase the probability of a Type I error?
- A.
Decreasing the sample size.

- B.
Increasing the sample size.

- C.
Decreasing the significance level.

- D.
Increasing the significance level.

- 7.Suppose that rather than the sample mean, we use another statistic that we'll call ~X to estimate the population mean. If the distribution of ~X is symmetric, what must be true for~X to be an unbiased estimator for the population mean?
- A.
The distribution of ~X must get narrower as the sample size increases

- B.
The variance of ~X should not depend on the sample size

- C.
The distribution of ~X must be centered at the population mean.

- D.
The value of ~X should approach the population mean as the sample size goes to infinity

- 8.The magnitude of the critical value for an upper one-tailed test at a 5% significance level will be:
- A.
Greater than the magnitude of the critical value for a two-tailed test using the same data at a 5% significance level.

- B.
Less than the magnitude of the critical value for a two-tailed test using the same data at a 5% significance level.

- C.
Equal to the magnitude of the critical value for a two-tailed test using the same data at a 5% significance level.

- D.
None of the above.