Below are sketches of residual plots from four
regressions. Characterize each plot by one of the
following letters, according to whether the plot reveals
(a) something's wrong with the regression
(b) residuals are heteroscedastic
(c) relationship is nonlinear
(d) heteroscedastic and nonlinear
(e) everything's fine
The next six questions refer to the list {0, 1, 3, 0, -3,
-1}.