portfolio theory - please show all workings so i can learn

table

year stock A stock B

2007 8 12

2008 21 27

2009 -27 -32

2010 11 18

2011 18 24

b. calculate the variance of stock a

d. calculate the variance for stock B

e. calculate the standard deviation of the expected return for stock b

f calculate the expected return for a portfolio of stock A 60% and stock b 40% weightings

g. if the distribution of the expected returns is approximately normal, calculate the range of expected returns for each stock (ie+or - one std dev about the mean expected return?

h. what do the results for the expected returns and standard deviation over the 5 year sample for each stock tell you