D use the above data to construct a 95 confidence

d. Use the above data to construct a 95% confidence interval for p
1
- p
2
2. Use the data in BUSI1013 Bank Dataset.xlsx (from Unit 1 Exercise Question 2) to
answer this question. ( 4 points each; 8 Points in total )
a. Perform a statistical test to see whether the proportion of members who would
recommend the Bank to their family and friends have increased because of the
change.

BUSI 1013 Statistics for Business – Exercise 9 3
b. Construct a 99% confidence interval for the difference of the proportions, before
and after the change, of members who would recommend the Bank to their family
and friends.
3
. 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 Total
West Region 15 35 50
Central Region 10 28 38