please solve clearly step by step.

When parking a car in a downtown parking lot, drivers pay according to the number of hours or fraction thereof. The probability distribution of the number of hours cars are parked has been estimated as follows: X 2 3 4 5 6 7 8 P(X) 0.22 0.139 0.102 0.077 0.06 0.034 0.022 0.346 Please give your answers to at least 4 decimal places. A. Mean = 4.538 B. Standard Deviation = The cost of parking is 4 dollars per hour. Calculate the mean and standard deviation of the amount of revenue each car generates. A. Mean = B. Standard Deviation =