I was tasked with comparing and running a regression between Walmart (WMT) and the S&P500. I have already calculated for the return (adjusted price _now - adjusted price)/adjusted price_old) and found the equity beta = 0.38 using Excel. The following questions in italics is what I need help with.

1.Get the Risk-Free Rate.

Find the current yield on a U.S. Treasury instrument that you feel represents the risk-free asset for a long-horizon project analysis.

You may get use one of the Treasury constant maturities from the website below:

https://www.federalreserve.gov/releases/h15/

Q: What is the best one to choose, if Walmart's risk free rate on Google is 0.7% , which would be make the most sense? Do I want a longer maturity date that leads to a higher rate of return or one that matches Walmarts risk free rate best? What is the best logic to use when selecting a yield in this case?

2.Get an estimate of the Market Risk Premium from the web site below (use implied equity premium):

http://pages.stern.nyu.edu/~adamodar/

Q: Is the implied equity premium the same as the market risk premium? (In this case, the 5.29% stated for October?

Q: When executing the CAPM equation, ER_i= R_f + B_i * (ER_m-R_f)

Would it be ER_i = R_f + 0.38 * (.0529) OR ER_i=R_f + 0.38 * (.0529 - R_f)

Q: How do you tell if a stock is over or underpriced against the cost of equity, what variables do you compare?