Question: Mean and SD of the number of matches. There are n balls labeled 1 through n, and n boxes labeled 1 through n. The tables are distributed randomly into the boxes, one in each box, so that all n permutations are equally likely. say that a match occurs at place i if the ball labeled i happens to fall in the box labeled i Let M be the total number of matches.
a) Find E(M).
b) find SD(M).
c) For very large n, what do you think is the approximate distribution of M? Give an intuitive explanation for your answer. Check that your answer makes sense in view of your answers to a) and b).