Estimate the sum betas (sum) for PNC and SLY in the following specification using 2 lags of the market and the same 120 day rolling window as above: r = + o Is&P500,t + B Is&P500,t-1 + B IS&P500,t-2 +& ; i=PNC or SLY Bsum = Bo + B + B Plot estimated sum betas against calendar time for PNC and SLY. Add these two graphs to the chart created in (2). Hint: Since this is a multiple regression, the Excel functions linest () and index() will come in handy. Use the help function for further clarification. Questions: Do you find evidence of delayed reaction to the market in PNC or SLY? How to test it empirically?