1. All tests of hypothesis are based on the assumption that a. the null hypothesis is false and should be rejected

b. the observed difference is important

c. the null hypothesis is true

d. Type I errors are more serious than Type II errors

2. If the test statistic falls in the critical region, we a. reject the null and conclude that the research hypothesis is true

b. reject the null and conclude that there is strong support for the research hypothesis

c. accept the null

d. fail to reject the null

3. Sixty percent of the respondents in a random sample drawn from a neighborhood are Democrats. The community as a whole is 75% Democrat. The difference between sample and population has been tested and the null hypothesis has been rejected. What might we conclude? a. a Type I error has been committed

b. a one-tailed test has been used

c. the neighborhood is significantly less likely to be Democrat

d. the difference is not significant

4. When testing a single sample mean for significance when the population standard deviation is unknown and sample size is 75, the correct sampling distribution is

a. the t distribution

b. the Z distribution

c. it makes no difference

d. t for a one-tailed test, Z for a two-tailed test

5. The t distribution, compared to the Z distribution, is

a. more skewed

b. more peaked for small samples but increasingly like the Z distribution as N increases

c. bimodal

d. flatter for small sample sizes but increasingly like the Z distribution as N increases

6. All other things being equal, with which of the following alpha levels would we be most likely to reject the null hypothesis?

a. .01

b. .001

c. .05

d. .10

7. A one-tailed test of significance could be used whenever

a. the researcher is interested in predicting a direction for the difference

b. the researcher feels like it

c. the null hypothesis is thought to be true

d. the alpha level exceeds 0.10

8. Do sex education classes and free clinics that offer counseling for teenagers reduce the number of pregnancies among teenagers? The appropriate test of hypothesis would be

a. a one-tailed test

b. a two-tailed test

c. cross-sectional

d. participant observation