A firm is seeking a method of forecasting its sales of a certain product in various parts of a country. The firms marketing effort is organized so that the country is divided into 12 territories. Within each territory, there is an exclusive distributor of the product. It is the general belief in the marketing department that the sales in each territory will be influenced by (i) number of television advertisement per week within the territory, and (ii) the number of salesmen employed by the distributor. The following data were obtained, Average Weekly Sales
Number TV adverts per week
Number of salesmen

10
2
3
12
3
5
15
5
5
20
7
6
14
4
5
22
7
8
18
5
6
11
3
5
17
6
6
21
8
8
19
7
7
24
9
7