Manual calculation only please :)

A company markets its products by direct mail. An experiment was conducted to study the effects of three factors on the customer response rate for a particular product. The three factors are: A = type of mail used (3rd class, 1st class), B = type of descriptive brochure (color, black- and-white), and C = offered price ($19.95, $24.95). The mailings are made to two groups of 8000 randomly selected customers, with 1000 customers in each group receiving each treatment combination. Each group of customers is considered as a replicate. The response variable is the number of orders placed. The experimental data are shown in table below: Coded Factors C Number of Orders Replicate 1 Replicate 2 50 54 44 42 46 48 42 43 49 46 48 45 47 48 56 54 A (class) B (type) C($) Factor Levels Low (-1) High (+1) 3rd 14 BW Color $19.95 $24.95 Run 1 2 3 4 5 6 7 8 (a) Analyze the data from this experiment. Which factors significantly affect the customer response rate? (b) Write down a regression model relating customer response to the important factors. (c) Analyze the residuals from this experiment. Are there any indications of model inadequacy? (d) What would you recommend to the company