Question 11.26

11.26 Residuals.

Refer to the fast-food data in Exercise 11.23. Find the residuals for the multiple regression used to predict market share based on the four explanatory variables.

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  1. Give a graphical summary of the distribution of the residuals. Are there any outliers in this distribution?
  2. Plot the residuals versus the number of franchises. Describe the plot and any unusual cases.
  3. Repeat part (b) with number of company-owned stores in place of number of franchises.
  4. Repeat part (b) with previous sales in place of number of franchises.