Question

Find expected value and variance of X for the following p.m.f. :

X	-2	-1	0	1	2
P(X)	0.2	0.3	0.1	0.15	0.25

Answer 1

We construct the following table to calculate E(X) and V(X) :

From the table,

Hence, E(X) = -0.05 and V(X) = 2.2475.