The final slice Here’s the residual plot corresponding to the regression model of Exercise 16:

The extreme case this time is Weight Watchers Pepperoni (makes sense, doesn’t it?). We can make one more indicator for Weight Watchers. Here’s the model:
Dependent variable is: Score R-squared = 77.1, R-squared (adjusted) = 69.4, s = 12.25 with 29 - 8 = 21 degrees of freedom

a) Compare this model with the others we’ve seen for these data. In what ways does this model seem better or worse than the others?

b) Do you think the indicator for Weight Watchers should be in the model? (Consider the effect that including it has had on the other coefficients also.)

c) What do the Consumers’ Union tasters seem to think makes for a really good pizza?

2 Studentized Residuals T + 20 40 + 60 80 Predicted Score