loess line not plotting correctly
问题 I'm having trouble fitting a loess smooth plus confidence limits to a scatterplot of residuals. My model is height ~ weight + chest circumference. To check linearity of chest circumference, I've fitted a model without chest circumference (i.e. height ~ weight), and plotted the residuals of this model against chest circumference. So far so good. I then tried to use loess() and predict() to plot a loess line, plus confidence limits. The result looks like this (in the picture I've only plotted