Ploting a skewed normal distribution in R

问题

How can I plot a skewed normal distribution in R, given the number of cases, the mean, standard deviation, median and the MAD.

A example would be that I have 1'196 cases, were the mean cost is 6'389, the standard deviation 5'158, the median 4'930 and the MAD 1'366. And we know that the billed case always cost something, so the cost must always be positive.

The best answer to this problem I could find is from https://math.stackexchange.com/a/17995/54064 and recommends the usage of the sn package. However I could not figure out how to use it for my concrete use case.

回答1:

I've had some success with fGarch package.

require("fGarch")
hist(rsnorm(1000, mean = 0, sd = 1, xi = 15))

mmm <- replicate(300, {
  x <- rsnorm(1196, mean = 6389, sd = 5158, xi = 15)
  c(mean = mean(x), sd = sd(x))
})

> mean(mmm[1, ])
[1] 6404.312
> mean(mmm[2, ])
[1] 5169.572

来源：https://stackoverflow.com/questions/26798938/ploting-a-skewed-normal-distribution-in-r