Hello, i am stuck on a question and i can't work it out.

if you have the number 1234, and you take all 24 permutations of it, you let X = the number of numbers that stay the same i.e 1324 = X=2 as 1 and 4 have stayed teh same, 4321 = X=0 as none have stayed the same.

Now the question says that E(X) = 1, yet when i work it out i get 2

X = {0,1,2,3,4} so E(X) = ((0+1+2+3+4)/5) = 2

where am i going wrong?