21/02/12 10:56:36.90 HI1nhh/q.net
母分散の推定
# URLﾘﾝｸ(yukiyanai.github.io)
rm(list=ls())
source('toolmini.R')
N=1e6
mu=170
sigma=6
n=100
pop=rnorm(N,mu,sigma)
pop=mu+sigma*(pop-mean(pop))/sd(pop)
mean(pop)
sd(pop)
Var<-function(x) sum((x-mean(x))^2)/length(x)
k=1e4
v0=replicate(k,var(sample(pop,n)))
v1=replicate(k,Var(sample(pop,n)))
summary(v0)
summary(v1)
Plot(10,60,0,0.08,asp=0)
abline(v=sigma^2,lty=3)
lines(density(v0))
lines(density(v1),col=2)
par(mfrow=c(2,1))
BEST::plotPost(v0, xlab='不偏分散')
BEST::plotPost(v1, xlab='標本分散')