Marguerita is a Certified Financial Planner (CFP), Chartered Retirement Planning Counselor (CRPC), Retirement Income Certified Professional (RICP), and a Chartered Socially Responsible Investing ...

Mary Hall is a editor for Investopedia's Advisor Insights, in addition to being the editor of several books and doctoral papers. Mary received her bachelor's in English from Kent State University with ...

In a previous issue of The American Statistician, Heffernan reexpressed the classical formula for the sample variance as a sum of squared pairwise differences. This result extends to the sample ...

Covariance is a statistical measure of how two assets move in relation to each other. It provides diversification and reduces the overall volatility of a portfolio. A positive covariance indicates ...

Methods of Rubin (1983) for robust estimation of a mean and covariance matrix and associated parameters are extended to analyse data with missing values. The methods are maximum likelihood (ML) for ...