Question

Compute the mean and variance of the following discrete probability distribution.

x P(x)
2 .50
8 .30
10 .20

Please assist and guide accordingly. Thank you so very much!

Answer 1

Here's a formula for the mean:
SUM[X * P(X)]
(Take each X times its respective P(X), then sum for a total. This will be your mean.)

Here's a formula for variance:
SUM[X^2 * P(X)] - mean^2
(Square each X. Take each X^2 times its respective P(X), then sum for a total. Subtract mean^2 from this value. This will be your variance.)

I hope this will help get you started.