Closing prices for SilTech and New Mines for the years 1997 - 2012 are shown below. calculate the total returns for each for the years 2012-1998 to 3 decimal places. note that the price for 1997 is used to calculate the total return for 1998. Assume that similar returns will continue in the future (i.e., average returns = expected returns). calculate the expected return, variance and standard deviation for both stocks and insert these values in the spreadsheet. use average, var, and stdev functions. calculate the covariance between these two stocks based on the 15 years of returns. plot the tradeoff between return and risk for these two stocks based on the calculation in (d). use the xy scatter diagram in excel