# The Number of Fixed Points in a Random Permutation

The Number of Fixed Points in a Random Permutation

For a random permutation of , let be the random variable that counts the number of digits that remain in their original position. This Demonstration allows you to compare the relative frequencies of obtained in a sample of size 400 with the exact and approximate distributions of . It also gives the sample mean and standard deviation.

(1,…,n)

X

X

X