Answer all parts. I'll upvote

Q1. A sample of promotion expenditure and sales of several e-commerce businesses in million taka are provided below. Promotion 22 15 4 4 7 10 12 15 17 15 Sales 150 100 80 100 90 120 110 120 130 140 (a) Show that a simple linear regression model can be fitted with these variables and state a linear model for these variables. How the least square method is used to estimate parameters in a 2 linear regression model? (b) At 5% level of significance test the hypothesis that the correlation is not positive. Based on 4 the test result comment on the sign of the regression coefficient. (c) Find the regression line of sales on promotion expenditure by estimating parameters. Also, 2+2 test the significance of slope coefficient at 5% level. (d) Find the 95% confidence interval for the mean sales with promotion expenditure of 7 million 3 taka and comment on your results