Question

Find the mean, variance and standard deviation for the probability distribution given below:

X	0	5	8	10
P(X)	0.598	0.136	0.208	0.058

A. Mean =

B. Variance =

C. Standard Deviation =

Answer 1

Solution:

x	P(x)	x * P(x)	x2 * P(x)
0	0.598	0	0
5	0.136	0.68	3.4
8	0.208	1.664	13.312
10	0.058	0.58	5.8
Sum	1	2.924	22.512

A.

Mean = X * P(X)

= 2.924

B.

Variance

= X 2 * P(X) - 2

=  22.512 - (2.924)2 = 13.96222

c.

Standard deviation = = 3.7366