Question: A bank recorded the number of ATM transactions made by its customers in one day. The number x of daily ATM transactions per customer can be approximated by the following probability distribution.
x P(x)
0 .22
1 .28
2 .20
3 .12
4 .09
5 .07
6 .02
Find:
(i) P(X≤4)
(ii) P(2 < X ≤ 5)
(iii) Find the mean of X
(iv) Find the standard deviation of X.