The following three residual plots i ii and iii were generat

The following three residual plots, (i), (ii), and (iii), were generated after fitting regression lines to the following three scatter plots, (a), (b), and (c). Which residual plot goes with which scatter plot? How do you know?

Solution

There are no unusual features in scatterplot (a), which goes with residual plot (iii)

Scatterplot (b) shows curvature, so it goes with residual plot (i).

In scatterplot (c), the points fan out as X increases, so this scatterplot goes with residual plot (ii).