The distribution of the number of chocolate chips x in a coo

The distribution of the number of chocolate chips (x) in a cookie is shown in the following table.

x:                  0           1            2              3    4            5                6              7              8

P(X = x): 0.02     0.03        0.04 0.11    0.14    0.24           0.22        0.15         0.05

Find the mean and the variance of the number of chocolate chips in a cookie. (Round your answers to two decimal places.)

Solution

E(x) = 4.97

V(x) = 1/n [ E(x^2) - {E(x)}^2]

V(x) = 1/8 [27.89 - 4.97^2 ]

V(x) = 0.266