$4.$ Using the following table to answer parts $($a$)-($c$).$ a$)$ What are the expected rates of return for Stocks INV and DEV? b$)$ What are the standard deviations of returns on Stocks INV and DEV? c$)$ Assume you invest $$8,000$ in Stock INV and $$2,000$ in Stock DEV, what is the expected return on your portfolio? Given the correlation between INV and DEV is $-0\mathrm{.}05,$ what is the standard deviation of the portfolio?