INTRODUCTION TO BUSINESS STATISTICS 7TH EDITION BY RONALD WEIERS – TEST BANK

Chapter 11: Hypothesis Tests Involving Two Sample Means
Student: ___________________________________________________________________________
1. True or False
When comparing the mean of two dependent samples, we are interested in only one variable: the difference between measurements for each person or object.
True False

2. True or False
A typical example of dependent samples occurs when we have before-and-after measures of the same individuals.
True False

3. True or False
An important factor in choosing between the pooled-variances t-test and the unequal-variances t-test is whether we can assume the population means might be equal.
True False

4. True or False
Although it is often associated only with small-sample tests, the t distribution is appropriate when the population standard deviations are unknown, regardless of how large or small the samples happen to be.
True False

5. True or False
When the population standard deviations are unknown and not assumed to be equal, pooling the sample standard deviations into a single estimate of their common population value is no longer applicable.
True False

6. True or False
When the population standard deviations are unknown and are not assumed to be equal, s1 and s2 must be used to estimate their respective population standard deviations, 1 and 2.
True False

7. True or False
The number of degrees of freedom associated with the unequal-variances t-test for comparing the means of two independent samples is n1 + n2 – 2.
True False

8. True or False
When either test can be applied to the same data, the z-test for comparing the means of two independent samples is preferable to the unequal-variances t-tests, especially when doing the test with computer assistance.
True False

9. True or False
The z-test requires no assumptions about the shape of the population distributions as long as both n1 and n2 are 30.
True False

10. True or False
The z-test approximation to the unequal variance t-test assumes that the population standard deviations, 1 and 2 , are known.
True False