Question

What is the purpose of residual plots?

A. to determine causation
B. to assess the type of relationship that exists between x and y
C. to check the appropriateness and fit of the regression equation for the data
D. to measure the variability in the residuals
E. to provide predictions for the response variable

Answer 1

C is the most appropriate answer. The residual plot lets you assess whether a linear regression is a good fit or not. If it is, you will see largely uniform dispersion of point along a horizontal. The degree of fit can also be seen looking at the variance.