我有这个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)
如何增加 geom_smooth 绘制的线条的粗细?