Question

Cincinnati Paint Company sells quality brands of paints though hardware stores throughout the United States. The company maintains a large sales force whose job is to call on existing customer as well as look for new business. The national sales manager is investigating the relationship between the number of sales calls made and the miles driven by the sales representative. Also, do the sales representatives who drive the most miles and make the most calls necessarily earn the most in sales commissions? To investigate, the vice president of sales selected a sample of 25 sales representatives and determined:

• The amount earned in commissions last month (Y)
• The number of miles driven last month (X1)
• The number of sales call made last month (X2)

The information is reported below:

Commissions	Calls	Driven
22	139	2371
13	132	2226
33	144	2731
38	142	3351
23	142	2289
47	142	3449
29	138	3114
38	139	3342
41	144	2842
32	134	2625
20	135	2121
13	137	2219
47	146	3463
38	146	3290
44	144	3103
29	147	2122
38	144	2791
37	149	3209
14	131	2287
34	144	2848
25	132	2690
27	132	2933
25	127	2671
43	154	2988
34	147	2829

Develop a regression equation including an interaction term. Is there a significant interaction between the number of sales calls and the miles driven?

(PROVIDE ANSWER WITHOUT USING ANY SOFTWARE OR EXCEL. PLEASE SHOW ALL MANUAL WORKINGS)

Answer 1