You invested in GM company, that operates in the aviation sector, in which you have invested. State of the economy Proba

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You invested in GM company, that operates in the aviation
sector, in which you have invested.
State of the economy Probability Expected
Return:
Bear:
Probability: 30%
Expected Return: -18%
Normal:
Probability: 50%
Expected Return: +6%
Bull:
Probability: 20%
Expected Return: +28%
a) Calculate the expected return and the standard deviation of
GM's return.