Interaction Plot in ggplot2

Question

I\'m trying to make interaction plot with ggplot2. My code is below:

library(ggplot2)
p <- qplot(as.factor(dose), len, data=ToothGrowth, geom         


        

Answer 1

a much easier way. without ddply. directly with ggplot2.

ggplot(ToothGrowth, aes(x = factor(dose) , y=len , group = supp, color = supp)) + 
  geom_boxplot() +
  geom_smooth(method = lm, se=F) +
  xlab("dose") +
  ylab("len")