Question

Calculate the standard deviation σ of X for the probability distribution. (Round your answer to two decimal places.) σ = x 0 1 2 3 P(X = x) 0.1 0.6 0.1 0.2

Answer 1

Solution :

x	P(x)	x * P(x)	x2 * P(x)
0	0.1	0	0
1	0.6	0.6	0.6
2	0.1	0.2	0.4
3	0.2	0.6	1.8
Sum	1	1.4	2.8

Mean = X * P(X)

= 1.4

Standard deviation =

=X 2 * P(X) - 2

=  2.8 - (1.4)2 = 0.84

Standard deviation = = 0.92