show your formula and process

Suppose the following information represents possible future returns for ATT stock next year State of Economy Probability of state of economy .20 .20 -20 -20 .20 1.00 Rate of return if state occurs 12% 6% -10% 22% 5% 4 (2.1) What is the expected rate of return for ATT common stock? (2.2) What is the variance of the return for ATT common stock