Another commonly seen residual plot is the fan-shaped plot.

A graph plots residuals that diverge from y = 0 as x increases.

Notice how the residuals for lower x values are more closely clustered around 0, while as x gets larger the residuals “fan out.” This is another pattern that would indicate that a linear model is not the best fit for relating y and x.

In general, a residual plot that indicates that a linear model is a good fit will have three characteristics:

  1. The residual plot will be roughly symmetrical.
  2. Residuals will be clustered within relatively low y values.
  3. There will be no clear pattern.