Choose one stock index (or one sector index) and one bond index. Go to yahoo/Finance and download 5 years of monthly data into your Excel for each stock index (Sector index) and bond index. Calculate the monthly rate of return (P1-P0/P0) for stock and bond index in your Excel. Compare the average return of your stock index ( Or sector index if you chose a sector index and not a stock index) with the average return of your bond index. Finally estimate the correlation of returns between bond index with stock or sector index over the past 5 years. (In Excel you can easily find the correlation of returns by using the CORREL function).