R Knoblauch/Maloney - MPDiR - Figure 2.1

• rebuild some graphics from the book Knoblauch/Maloney: Modeling Psychophysical Data
  
• from chapter 2 (Modeling), plotting age dependence of threshold for each level combination of Mtype and Sex using ggplot2 (page 27)
  
• instead of the two panels we use two smooth() layers, loess is the default method for group sizes < 1000, so we only have to tell ggplot to use "lm" as method for one layer


• we set se to F (se=F) in both of them which prevents the convidence intervals from being plotted
  


• size, linetype, and colour are the corresponding parameters to lwd, lty, and col respectively
  


• a nice list of line types and shapes of points
  


• to plot a separate figure for every combination we use facet_wrap()
  

library(MPDiR)
data(Motion)
library(ggplot2)
ggplot(Motion, aes(x=LnAge,y=LnThresh)) + 
  geom_point() +
  geom_smooth(method="lm",se=F) +
  geom_smooth(se=F, size=2, linetype=2, colour="black") +
  facet_grid(Sex ~ Mtype,as.table=T)