A consumer psychologist wanted to know if customers are influenced by sales clerks who smile more. The psychologist gave special instructions to clerks at eight stores at the start of a week and recorded sales for the week. Clerks in four of the randomly selected stores received instructions to be especially courteous and to be sure to smile a lot. Clerks at four other stores were simply instructed to be especially courteous. Sales (in thousands of dollars) for the four stores in the Smile condition were 36, 40, 36, and 44; sales for the four stores in the Control condition were 40, 31, 27, and 30. Use the .05 significance level to determine if customers are influenced by sales clerks who smile a lot.

Msmile = 39

Mcontrol = 32

SSsmile = 44

SScontrol = 94

Mdifference = 7

SSdifference = 178

Difference = Smile - Control

2. What is the null hypothesis?

3. What is the research hypothesis?

4. What is the comparison mean?

5. What is the comparison standard deviation?

6. Explain how you found/calculated the comparison mean and the comparison standard

deviation. Detail the process (i.e., the steps) in calculating these statistics.

7. What is/are the cutoff(s)?

a. +1.64

b. 1.96

c. 2.365

d. 2.447

8. What is the sample score (i.e., the test statistic)?

9. Upload a sketch for this hypothesis test labeling:

a) the cutoff(s)

b) the rejection region(s)

c) the sample score

10. What is your conclusion for this hypothesis test?

a. reject the null

b. accept the research hypothesis

c. accept the null

d. fail to reject the null

11. Explain how you came to your conclusion about the null.