a)A company dealing with cosmetics wishes to invest in product promotion through door-to-door marketing. In a duration of Seven months, the annual sales and the amount invested in marketingwas as shown below

Amount Used in marketing (Ksh "million')

6

8

10

12

15

17

20

Sales (Khs 'millions)

200

190

240

210

270

280

290

By identifying the dependent and the independent variables;

i)Estimate the regression line for the data(7 marks)

ii)Interpret the coefficients in part (i) above(3 marks)

iii)Estimate the volume of sales if the company decided to invest Ksh 25 million in door-to-door marketing(2 marks)