n <- 100

x <- rnorm(n, mean=0,sd=1)

hist(x)

dnorm(x)

sigmax <- sd(x)

sigma2x <- var(x)

plot(x,dnorm(x))

xbar <- sum(x)/n

xvar <- sum((x-xbar)^2)/n

var(x)

sum(log(dnorm(x,xbar,sqrt(xvar))))

plot(x,dnorm(x,xbar,sqrt(xvar)))

matplot(x,cbind(dnorm(x,xbar,sqrt(xvar)),dnorm(x)))