Question

a) Perform a statistical test to see whether the average loans of customers before the change at the Bank of America and Wells Fargo are different.

Loans before the change at Bank of America:  

51.2
46.1
43.4
44.1
50.2
39.1
35.6
49.3
37.4
49.3
52.9
50.0
37.7
53.0
45.7
36.9
43.4
41.2
54.9
55.0
36.8
38.6
37.1
49.9
47.2
46.0
39.9
53.9
35.5
54.3
36.8
42.0
50.5
50.3
44.7
37.6
35.3
39.8
48.7
51.5

Loans before the change at Wells Fargo:

50.4
42.9
52.2
44.7
40.6
38.2
46.6
47.0
53.5
36.5
47.7
45.8
44.5
38.3
54.3
54.5
44.5
42.4
52.3
50.7
43.7
54.5
38.7
44.5
52.5
53.0
48.6

Increase in loans at BoA:

12.2
8.4
1.3
13.2
5.5
7.4
14.0
-5.1
23.2
7.2
-3.9
12.8
23.7
-2.4
-1.0
7.8
6.7
18.0
-0.1
0.4
8.9
20.5
18.1
9.6
-1.3
1.2
18.5
4.2
28.0
8.7
24.2
5.4
-6.1
13.4
5.0
20.4
13.5
17.4
14.8
-7.9
Increase in loans at Wells Fargo

4.5
16.1
5.0
7.5
19.3
10.0
12.9
11.3
5.1
20.1
14.4
13.1
13.3
10.3
-5.1
-2.1
18.4
13.9
10.3
-4.8
17.3
-1.9
6.9
12.3
0.8
-5.7
10.1
8.2

b) Construct a 95% confidence interval for the difference of average loans of customers before the change at the Bank of America and Well Fargo branch.

Answer 1