Answer:
Variance of the return on this common stock is 0.15%
Explanation:
Note: See the attached excel file for the calculation of the variance of the returns on this common stock.
Note that the probability of a normal economy can be obtained as follows:
Probability of normal economy = 100% - Probability of a boom - Probability of a recession = 100% - 12% - 10% = 78%
These probabilities are used in the attached excel file.