library(tigerstats)

n_list<-c(2,5,10,30) # Ç¥º»¼ö(n)
df_list<-n_list-1 # ÀÚÀ¯µµ

curve(dt(x, 1, ncp=0), col="blue", xlim=c(-4, 4), ylim=c(0, 0.5), xlab="t", ylab="f(t)")
curve(dt(x, 4, ncp=0), add=T, col="red", xlim=c(-4, 4), ylim=c(0, 0.5), xlab="t", ylab="f(t)")
curve(dt(x, 9, ncp=0), add=T, col="green", xlim=c(-4, 4), ylim=c(0, 0.5), xlab="t", ylab="f(t)")
curve(dt(x, 29, ncp=0), add=T, col="black", xlim=c(-4, 4), ylim=c(0, 0.5), xlab="t", ylab="f(t)")

par(mfrow=c(2,2))

for (i in 1:length(df_list)) {
  
  curve(dt(x, df_list[i], ncp=0), xlim=c(-4, 4), ylim=c(0, 0.5), xlab="t", ylab="f(t)", main=paste("df=", df_list[i]))
}

qnormGC(0.99997,region="below",m=0,s=1, graph=T)
curve(dt(x, 1, ncp=0), add=T, col="black", xlim=c(-4, 4), ylim=c(0, 0.5), xlab="t", ylab="f(t)")

qnormGC(0.99997,region="below",m=0,s=1, graph=T)
curve(dt(x, 4, ncp=0), add=T, col="red", xlim=c(-4, 4), ylim=c(0, 0.5), xlab="t", ylab="f(t)")

qnormGC(0.99997,region="below",m=0,s=1, graph=T)
curve(dt(x, 9, ncp=0), add=T, col="green", xlim=c(-4, 4), ylim=c(0, 0.5), xlab="t", ylab="f(t)")

qnormGC(0.99997,region="below",m=0,s=1, graph=T)
curve(dt(x, 29, ncp=0), add=T, col="black", xlim=c(-4, 4), ylim=c(0, 0.5), xlab="t", ylab="f(t)")