What conditions would justify the assumption of a constant contribution margin per customer? Do you think those conditions are likely to hold here? To support your conclusions, show a scatter plot of the sample data, and then use the sample data to run a regression of purchase costs (dependent variable) on purchase revenues (independent variable). [Hint: What is the meaning of the intercept term of your regression results?]

Day Customers:

Purchase Revenue	Purchase Cost
36.14	26.58
38.33	26.07
43.54	29.6
26.17	20.79
42.55	28.93
33.58	21.84
27.85	19.94
33.61	20.85
34.03	25.14
37.57	24.54
35.26	25.98
44.08	30.98
35.81	25.35
47.29	31.16
48.66	35.09
45.11	33.68
40.33	28.42
46.85	34.86
34.12	24.2
34.85	20.7
30.07	23.45
29.79	21.26
36.74	24.98
35.06	26.84
28.89	20.64
24.38	13.58
30.4	22.67
40.94	29.84
41.56	28.26
30.43	22.69

Evening Customers:

Purchase Revenue	Purchase Cost
43.01	32.25
38.25	25.01
38.63	23.27
39.17	28.64
34.51	22.47
37.02	25.18
36.87	25.07
37.64	26.59
37.93	22.79
35.88	27.4
39.59	26.92
41.81	26.43
35.27	23.98
38.39	27.11
56.01	35.09
40.92	29.83
33.83	21.01
41.24	29.04
29.99	19.39
50.61	36.42
36.21	26.62
47.07	30.01
36.85	28.06
40.1	25.26
39.26	25.69
40.89	29.81
33.05	23.48
33.85	20.02
27.24	20.52
38.08	24.9

All Customers:

Purchase Revenue	Purchase Cost
36.14	26.58
38.33	26.07
43.54	29.6
26.17	20.79
42.55	28.93
33.58	21.84
27.85	19.94
33.61	20.85
34.03	25.14
37.57	24.54
35.26	25.98
44.08	30.98
35.81	25.35
47.29	31.16
48.66	35.09
45.11	33.68
40.33	28.42
46.85	34.86
34.12	24.2
34.85	20.7
30.07	23.45
29.79	21.26
36.74	24.98
35.06	26.84
28.89	20.64
24.38	13.58
30.4	22.67
40.94	29.84
41.56	28.26
30.43	22.69
43.01	32.25
38.25	25.01
38.63	23.27
39.17	28.64
34.51	22.47
37.02	25.18
36.87	25.07
37.64	26.59
37.93	22.79
35.88	27.4
39.59	26.92
41.81	26.43
35.27	23.98
38.39	27.11
56.01	35.09
40.92	29.83
33.83	21.01
41.24	29.04
29.99	19.39
50.61	36.42
36.21	26.62
47.07	30.01
36.85	28.06
40.1	25.26
39.26	25.69
40.89	29.81
33.05	23.48
33.85	20.02
27.24	20.52
38.08	24.9