Seeing if data is normally distributed in R

Question

Can someone please help me fill in the following function in R:

#data is a single vector of decimal values
normally.distributed <- function(data) {
if(dat         


        

Answer 1

The Anderson-Darling test is also be useful.

library(nortest)
ad.test(data)

Answer 2

when you perform a test, you ever have the probabilty to reject the null hypothesis when it is true.

See the nextt R code:

p=function(n){
  x=rnorm(n,0,1)
  s=shapiro.test(x)
  s$p.value
}

rep1=replicate(1000,p(5))
rep2=replicate(1000,p(100))
plot(density(rep1))
lines(density(rep2),col="blue")
abline(v=0.05,lty=3)

The graph shows that whether you have a sample size small or big a 5% of the times you have a chance to reject the null hypothesis when it s true (a Type-I error)