4. I have given you the monthly rates of return for Pubali Bank and RAK Ceramic for a 6-month time period. Month 1 2 3 4 5 6 Pubali Bank -6% 6% -4% RAK Ceramic 10 -2% -10% 12% -6% 4% 12% -3% 5% What is the correlation coefficient between the rates of return of the two stocks? Show your work