Consider this hypothesis test:

H0: p1 - p2 = < 0

Ha: p1 - p2 > 0

Here p1 is the population proportion of "yes" of Population 1 and p2 is the population

proportion of "yes" of Population 2. Use the statistics data from a simple random

sample of each of the two populations to complete the following: (8 points)

Population 1 Population 2

Sample Size (n) 500 700

Number of "yes" 400 560

a. Compute the test statistic z.

b. What is the p-value?

c. Should H0 be rejected? Use the p-value and a level of significance of 0.05 to justify your answer

d. Use the above data to construct a 95% confidence interval for p1 - p2

A national retailer has completed an internal survey on its social media strategy. The key question in the survey is whether the stores managers think that the recently-launched social media strategy is effective. The following is the output of a statistical analysis of the data:

Social Media Strategy is effective

Store Managers No Yes

West Region 20 35

Central Region 15 35

East Region 40 55

Based on this output, can the retailer conclude that the opinion of the store managers on the whether the recently-launched social media strategy is effective is dependent on which region they belong to? Use a chi square test and a level of significance of 0.05.