Aesthetics must be either length 1 or the same as the data (500)

Question

I am trying to reproduce this boxplots from a linear regression model output. my model and the code I used is below. I am getting this error "Aesthetics must be either length 1 or the same as the data (500)." What am I doing wrong? Please help!

out <- lm(L_SHUCK ~ L_VOLUME+CLASS, data = mydata)

r <- residuals(out)

ggplot(out , aes (x = CLASS , y = r, group = CLASS)) + geom_boxplot()

Answer 1

You can't really just put in the output of the lm object to do this. You need to do something along these lines:

out = lm(mpg ~ wt + as.factor(am), mtcars)
r = residuals(out)
mtcars$residuals = r

ggplot(mtcars) + geom_boxplot(aes(x = as.factor(am), y = residuals))

I think a good ggplot2 tutorial would help you understand what is going on exactly, eg this one I wrote .