# Derangement - Hat check problem

A discussion of the derangement problem with links to demonstrations of the concept. The number in the derangements as the number of objects approaches infinity is shown to be equal to $e$. The probability of matching is not found. A good link in the right hand column, "The Number of Fixed Points in a Random Permutation" allows you to compare the relative frequencies of digits that remain in their own position after random permutation of size 400 with the exact and approximate distributions. It also gives the sample mean and standard deviation.
Identifier:
http://mathworld.wolfram.com/Derangement.html
Rating:
Creator(s):
Wolfram MathWorld
Cataloger:
Carolyn Cuff
Publisher:
Wolfram MathWorld
Rights:
2011 Wolfram Alpha LLC&#226;&#128;&#148;A Wolfram Research Company