P$8-20$ Portfolio efficiency The following table provides the expected return and standard

deviation for four portfolios. Plot each portfolio's risk$-$return combination on a

graph and identify which are the efficient versus inefficient portolios.

P$8-21$ Correlation, risk, and return Nikki Williams wishes to evaluate the risk and return

behaviors associated with various combinations of assets $x$ and $Y$ under three as$-$

sumed degrees of correlation: perfectly positive, uncorrelated, and perfectly negative.

The expected returns and standard deviations calculated for each of the assets are

shown in the following table.