Using the S&P500, AAPL, and WMT data from the daily from 2/4/16 to 2/4/21, construct the variance-covariance matrix. Calculate the beta between AAPL and the S&P 500, WMT and the S&P 500, and AAPL and WMT combined to the S&P 500. Use daily returns for the entire 5-year time series. Data for the S&P 500, AAPL, and WMT should be collected from yahoo finance.