Please HELP! I got the first part but confused on the 2nd part:

Problem 6-05 Expected Return: Discrete Distribution

A stock's return has the following distribution:

Demand for the Company's Products	Probability of This Demand Occurring			Rate of Return if This Demand Occurs (%)
Weak		0.1		-50%
Below average		0.2		-6
Average		0.4		11
Above average		0.2		30
Strong		0.1		70
		1.0

Calculate the stock's expected return. Round your answer to two decimal places. %11.2

Calculate the standard deviation. Round your answer to two decimal places. %