Spreadsheet Problem As discussed the text, beta $$stimates for one firm will vary depending on various factors such as the time over which the estimation is conducted, the market portfolio proxy, and the return intervals. You will demonstrate this variation using returns for Microsoft. $($L$*$ LG$10-4)$

a$.$ Using all $45$ monthly returns for Microsoft and the two stock market indexes, compute Microsoft's beta using the S&P $500$ Index as the market proxy. Then compute the beta using the NASDAQ index as the market portfolio proxy. Compare the two beta estimates.

B$.$ Now estimate the beta using only the most recent $30$ monthly returns and the S&P $500$ Index. Compare the beta estimate to the estimate in part $($a$)$ when using the S&P $500$ Index and all $45$ monthly returns.

C$.$ Estimate Microsoft's beta using the following quarterly returns.

Compare the estimate to the ones from parts $($a$)$ and $($b$).$

$\backslash$table$[[,$A$,$B$,$C$],[1,$Date,MSFT$,$S&P$500],[2,$Q$42020,6\mathrm{.}02\%,11\mathrm{.}69\%$