Suppose X is the amount of money a person earns in an hour w

Suppose X is the amount of money a person earns in an hour where

P(X = $5) =0.2, P(X =$10) = 0.1, P(X=$15) =0.5 and P(X=$20) = 0.2.

How much money would the person earn on average?

Solution

E(X)=sum(X*P(X))

E(X)=1+1+7.5=9.5