A supermarket chain staged a promotion for organic vegetables. The actual sales (Sales) of organic vegetables for the weekend of the promotion were obtained from scanner data at the checkout. Three explanatory variables under consideration for modeling SALES were the size of the store (SqFeet) (in thousands of square feet), the number of customers processed in the store (NumCusts) (in hundreds), and the average size of purchase (AvgSize), which was also obtained from the scanner data. A scatterplot matrix is shown here.

a. Is there any evidence of collinearity in the scatterplots?
b. Does the scatterplot matrix reveal any other problems associated with the data?
c. What other diagnostics of collinearity would you suggest for this problem?

Transcribed Image Text:

2000 1500 1000 500 Sales 20- 15 10 SqFeet 35 30 25 NunCusts 15 10 80 ■ 70 60 AvgSize 500 1000 2000 5 10 15 20 10 15 20 25 30 35 50 60 70 80