Myers Business Systems is evaluating the introduction of a new product. The possible levels of unit sales and the probabilities of their occurrence are given next:

Possible Market Reaction	Sales in Units	Probability
Low response	20	0.10
Moderate response	40	0.30
High response	55	0.40
Very high response	70	0.20

a. What is the expected value of unit sales for the new product?

b. What is the standard deviation of unit sales?