posted by Dee .
Dee's store monthly sales for April, May, June are three independent random variables with means and variances as follow:
a) find the mean and standard deviation of the total sales for the 2nd quarter (3 month period).
-for mean, do you just add the means together and for stdev, do you just add the variance together and square root it?
b) If the store manager is paid by a base monthly salary of $2000 plus 10% of the monthly sales as commission, what is the mean and standard deviation of his monthly salary for May?
-how do you do this part?