15.6 F 분포 (F Distribution) : stat_function(fun = df)

# F분포 : fun = df
ggplot(data.frame(x=c(0,5)), aes(x=x)) +
     stat_function(fun = stats::df, args=list(df1=9, df2=9), colour="blue", size=0.5) +
     stat_function(fun=stats::df, args=list(df1=10, df2=30), colour="red", size=0.5) +
     stat_function(fun=stats::df, args=list(df1=50, df2=100), colour="yellow", size=0.5) +
     annotate("segment", x=3, xend=3.5, y=1.4, yend=1.4, colour="blue", size=0.5) +
     annotate("segment", x=3, xend=3.5, y=1.2, yend=1.2, colour="red", size=0.5) + 
     annotate("segment", x=3, xend=3.5, y=1.0, yend=1.0, colour="yellow", size=0.5) + 
     annotate("text", x=4.3, y=1.4, label="F(df1=9, df2=9)") +
     annotate("text", x=4.3, y=1.2, label="F(df1=10, df2=30)") + 
     annotate("text", x=4.3, y=1.0, label="F(df1=50, df2=100)") +
     ggtitle("F Distribution")