A person sells new cars for a company. They usually sells the largest number of cars on Saturday. He established the following prob

A person sells new cars for a company. They usually sells the largest number of cars on Saturday. He established the following probability distribution for the number of cars he expects to sell on a particular Saturday.

Number of cars sold (X) —– 1 2 3 4

Probability: P(X) —– 0.3???? 0.4 0.1 0.2

??

What is the standard deviation?