Chapter 8

Multiple Choice

Identify the choice that best completes the statement or answers the question.

____1.The central problem in the case of two-sample hypothesis test is to determine

a.

if the samples are random

b.

if sample statistics are the same as those of the sampling distribution

c.

if the parameters are representative of the populations

d.

if two populations differ significantly on the trait in question

____2.When testing for the significance of the difference between two sample means, the null hypothesis states

a.

₁ = ₂

b.

m > 0

c.

m₁ = m₂

d.

s₁ = s₂

____3.When testing for the significance of the difference between two samples, the null hypothesis reminds us that our interest is on differences between the

a.

samples

b.

populations

c.

sampling distributions

d.

standard deviations

____4.Rejection of the null hypothesis in the two-sample case implies that the

a.

samples are different on the trait of interest

b.

populations from which the samples are drawn are different on the trait of interest

c.

samples are not different on the trait of interest

d.

populations from which the samples are drawn are not different on the trait of interest

____5.When conducting hypothesis tests for two sample means, the test statistic is

a.

alpha

b.

the difference in sample means

c.

the degrees of freedom

d.

the difference in the population means

____6.When conducting hypothesis tests for two sample means, the term m₁ - m₂ in the numerator of the formula reduces to zero because

a.

the standard deviations are calculated first

b.

the tests are conducted at very low alpha levels

c.

the samples are independent as well as random

d.

the null hypothesis is assumed to be true

____7.For testing the difference between two sample means, the level of measurement is assumed to be

a.

Nominal

b.

Ordinal

c.

interval-ratio

d.

any of the above

____8.A researcher conducted a survey to determine if older people have different feelings about abortion than younger people. He used an alpha level of 0.05 (Z critical = 1.96) to test for significance and found that his computed test statistic was 2.76. He may conclude that

a.

the difference occurred by random chance

b.

the difference did not occur by random chance

c.

the samples are not independent

d.

the alpha level was too low

____9.When testing for the significance of the difference between sample means with small samples, the proper sampling distribution is

a.

the alpha distribution

b.

the beta distribution

c.

the Z distribution

d.

the t distribution

____10.Four test of significance were conducted on the same set of results:

For test 1: alpha = 0.05, two-tailed test.

For test 2: alpha = 0.10, one-tailed test.

For test 3: alpha = 0.01, two-tailed test.

For test 4: alpha = 0.01, one-tailed test.

Which test is most likely to result in a rejection of the null hypothesis?

a.

Test 1

b.

Test 2

c.

Test 3

d.

Test 4

____11.The larger the sample size, the

a.

more important the observed difference

b.

more likely we are to reject the null hypothesis

c.

less likely we are to reject the null hypothesis

d.

lower the Z score

____12.A difference between samples that is shown to be statistically significant is always

a.

theoretically important

b.

practically important

c.

sociologically important

d.

none of the above

____13.Very large random samples of Catholics and Protestants have been questioned about their opinions on cohabitation. Forty-six percent of the Protestant and 47% of the Catholics approve of males and females living together without being married. The difference has been tested and found to be statistically significant. What is the most reasonable conclusion?

a.

This is a statistically significant and important difference

b.

This difference may be statistically significant but it seems unimportant

c.

This difference is due to random chance

d.

The researcher should have used sample means rather than proportions in this situation

14. Give the most appropriate null hypothesis for the above SPSS output.

15. Give the most appropriate alternative hypothesis for the above SPSS output.

16. Give the confidence interval for the difference between the population means.

17. Is the test one-tailed or two-tailed?

18. Give and interpret the result of the hypothesis test.

19. In this case, what would a type 1 error mean? Can a type 1 error occur with the above SPSS output?

20. What is the probability the means are equal? Different?