a) Suppose we form a portfolio invested in Toyota and Ford stocks. Cells B3:C5 in the spreadsheet below display the mean return, variance, and standard deviation of the Toyota and Ford returns, respectively. Cell B6 reports i) Compute the standard deviation of Toyota (Cell BS) and Ford (Cell C5) to two decimal places and interpret th result, Show your calculations in detail, including the theoretical as well as the excel formula. [5 marks] ii) Compute the mean and variance of this portfolio, as well as its standard deviation (Cells B12:814), Show your calculations in detail, including the theoretical as weil as the excel formula. [15 marks]