Suppose that the index model for stocks A and $B$ is estimated from excess returns with the following results:

$R_A=2\mathrm{.}20\%+0\mathrm{.}80R_M+e_A$

$R_B=-2\mathrm{.}20\%+1\mathrm{.}20R_M+e_B$

${}_M=248$;$R-$square $A=0\mathrm{.}16$;$R-$square $B=0\mathrm{.}12$

Assume you create portfolio $P$ with investment proportions of $0\mathrm{.}70$ in A and $0\mathrm{.}30$ in $B.$

Required:

a$.$ What is the standard deviation of the portfolio?

Note: Do not round your intermediate calculations. Round your answer to $2$ decimal places. Calculate using numbers in decimal form, not percentages. For example use $"20"$ for calculation if standard deviation is provided as $20\%.$

b$.$ What is the beta of your portfolio?

Note: Do not round your intermediate calculations. Round your answer to $2$ decimal places. Calculate using numbers in decimal form, not percentages. For example use $"20"$ for calculation if standard deviation is provided as $20\%.$

c$.$ What is the firm$-$specific variance of your portfolio?

Note: Do not round your intermediate calculations. Round your answer to $3$ decimal places. Calculate using numbers in decimal form, not percentages. For example use $"20"$ for calculation if standard deviation is provided as $20\%.$

d$.$ What is the covariance between the portfolio and the market index?

Note: Do not round your intermediate calculations. Round your answer to $2$ decimal places. Calculate using numbers in decimal form, not percentages. For example use $"20"$ for calculation if standard deviation is provided as $20\%.$