$($Security market line$)$ You are considering the construction of a portfolio comprised of equal investments in each of four different stocks. The betas for each stock are found below.

$\backslash$table$[[$Asset$,$Beta$],[$A$,230],[$B$,0\mathrm{.}80],[$C$,0\mathrm{.}60],[$D$,-160]]$

$($Click on the icon bin order to copy its contents into a spreadsheet$)$

a$.$ What is the portfolio beta for your proposed investment portfolio?

b$.$ How would a $25$ percent increase in the expected return on the market impact the expected return of your portfolio?

c$.$ How would a $25$ percent decrease in the expected return on the market impact the expected return on each asset?

d$.$ If you are interested in decreasing the beta of your portfolio by changing your portfolio allocation in two stocks, which stock would you decrease and which would you increase? Why?

a$.$ The portfolio beta for your proposed investment portfolio is $($Round to three decimal places$)$