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 effectiveStore ManagersNoYesWest Region 15 Central Region 10 East Region 45 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. (4 points)
35
28
50
BUSI
1013:
S
TATISTICS FOR
B
USINESS
12
Social Media Strategy is effective
Store Managers
No
Yes
West Region
15
35
Central Region
10
28
East Region
45
50
50
38
95
70
113
183
Expected
19.13
30.87
14.54
23.46
36.34
58.66
Difference Square/Expected
0.890
0.551
1.415
0.877
2.064
1.279
Chi Square Statistic =
7.076
Since chi square statistic=7.076 >5.991, we reject H
0
and conclude that the
recently-launched social media strategy is effective is dependent on which region
they belong to
4. Use the data in
BUSI1013 Bank Dataset.xlsx
(from Unit 1 Exercise Question 2) to
perform a statistical test on whether a customer would recommend the Bank to their
BUSI
1013:
S
TATISTICS FOR
B
USINESS
13
Recommend Before
Gender
Yes
No
Male
28
49
Female
22
53
family and friends before the change is dependent on the gender of the customer. (
4
points
)
77
75
50
102
152
Expected
25.33
51.67
24.67
50.33
Difference Square/Expected
0.282
0.138
0.289
0.142
Test Statistic
0.851
