Sampson Corp. is evaluating the introduction of a new product. The possiable levels of unit sales and the probabilities of their occurrence are shown next:

Possible Market Reaction	Sales in units	Probabilities
Low Response	30	0.10
Moderate response	50	0.20
High Response	75	0.40
Very High Response	90	0.30

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

b. What is the standard deviation of unit sales?