1. A portfolio management organization analyzes 65 stocks and constructs a mean-variance efficient portfolio using only these 65 securities.

a.	How many estimates of expected returns, variances, and covariances are needed to optimize this portfolio?

Estimates of expected returns _______??
Estimates of variances _______??
Estimates of covariances _______??
Total estimates ________??

b.	If one could safely assume that stock market returns closely resemble a single-index structure, how many estimates would be needed?

Estimates _______??