In what special case does the regression of on match the regression of on , so that if two fitted lines were drawn on the same plot, the lines would coincide? From looking at this plot of the...

In what special case does the regression of

on

match the regression of

on
, so that if two fitted lines were drawn on the same plot, the lines would coincide?

From looking at this plot of the residuals from a linear equation, estimate the value of
.