Since the sample size is very small, (only 5 years), n-1 should be used instead of n to get an unbiased estimator for the variance.

Calculate the portfolio return in each year, and the expected rate of return and standard deviation for stocks w, y and portfolio wy. (We invest 50% in Stock W.)

Please try to not using in excel, if using with formulae that would be great, thank you!

Example 9: Diversification with stocks with partial correlation (-1