I keep doing this problem over and over and get a different answer each time. I would appreciate some help.

Here are the returns on two stocks.

Digital Cheese Executive Fruit

January +15 +8

February 2 +1

March +4 +6

April +6 +16

May 3 +2

June +2 +6

July 1 2

August 7 1

Required:

a-1.Calculate the variance and standard deviation of each stock.

a-2.Which stock is riskier if held on its own?

b.Now calculate the returns in each month of a portfolio that invests an equal amount each month in the two stocks.

c.Is the variance more or less than halfway between the variance of the two individual stocks?