n the last 5 years, Tesla had an average monthly return of 4.73% with a standard deviation of 16.8%. Over the same period, Starbucks Inc had an average monthly return of 1.72% with a standard deviation of 5.6%. What was the average monthly return to a portfolio of 50% TSLA and 50% SBUX?

I need to see how to find the correlation coefficient and plug it into the formula