# Section 1-19-10

8 Questions  Settings  Related Topics
• 1.
Suppose we can reject the null hypothesis that u>=50 at the 5% signi ficance level. Which of the following statements is de finitely true?
• A.

We can reject the null hypothesis that u = 50 at the 5% signi ficance level.

• B.

We can reject the null hypothesis that u>= 50 at the 10% signi ficance 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% signi ficance 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% confi dence 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% signi ficance level.

• D.

All of the above are true.

• 4.
Which of the following would narrow the con fidence interval for the population mean?
• A.

Decreasing the sample size.

• B.

Decreasing the signi ficance level.

• C.

Both (a) and (b) would narrow the con fidence interval

• D.

Neither (a) nor (b) would narrow the confi dence interval.

• 5.
The probability of a Type I error when doing a two-tailed hypothesis test at a 5% signifi cance level is:
• A.

Equal to the probability of a Type I error when doing a one-tailed hypothesis test at a 2.5% signi ficance level.

• B.

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

• C.

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

• D.

Equal to the probability of a Type I error when doing a one-tailed hypothesis test at a 20% signifi cance 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 signi ficance level.

• D.

Increasing the signi ficance 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 infi nity

• 8.
The magnitude of the critical value for an upper one-tailed test at a 5% signi ficance level will be:
• A.

Greater than the magnitude of the critical value for a two-tailed test using the same data at a 5% signi ficance level.

• B.

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

• C.

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

• D.

None of the above.