I'm trying to regress some simple pooled data. My data has 60 observations and three columns: Weight, Height, and Sex (female=1, male=0). If I regress thus, Weight ~ Height + Sex, my model is fairly satisfactory, but the residuals are not homoscedastic (green errors are male, blue female): ![plot](http://i1267.photobucket.com/albums/jj541/nbahmanyar/Rplot_zps69001b34.png) I tried regressing on the log of Weight and/or Height, but that didn't do much. What should I do to make the residuals homescedastic and/or make my model more accurate? Any help would be appreciated. **Edit**