Question

Identify two graphs used in a residual analysis to check the Assumptions 1-3 for regression inferences, and explain the reasoning behind their use:

Short answer

Their use is justified because failure to meet these two conditions calls into question the validity of one or more of the assumptions for regression inferences for the variables under consideration.

Step-by-step solution

Given Information

The given assumption for regression inferences is 1-3

Explanation

- The residuals' normal probability plot should be roughly linear.

- A plot of the residuals against the predictor variable values should be symmetric about the$x$ axis and fall roughly in a horizontal band.

Their use is justified because failure to meet these two conditions calls into question the validity of one or more of the assumptions for regression inferences for the variables under consideration.