please help!

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:

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

Note: Do not round intermediate calculations and round your answer to the nearest whole unit.

b$.$ What is the standard deviation of unit sales?

Note: Do not round intermediate calculations. Round your answer to $2$ decimal places.

Standard deviation

units