increasing the line thickness of geom_smooth

Question

I have this ggplot:

ggplot(dt.m, aes(x=pct.on.OAC.cont,y=Number.of.Practices, fill=Age.Group)) +
    geom_bar(stat="identity",position=position_dodge()) +   
    geom_smooth(aes(x=pct.on.OAC.cont,y=Number.of.Practices, colour=Age.Group), se=F)

How can I increase the thickness of the lines drawn by geom_smooth ?

Answer 1

Do the size argument do what you want:

+ geom_smooth(aes(x=pct.on.OAC.cont, y=Number.of.Practices, colour=Age.Group), 
               se=F, size=10)

alternatively, you could change size to lwd, but it is standard to use size.