Geometric Mean - A measure of central tendency calculated by multiplying a series of numbers and taking the nth root of the product, where n is the number of items in the series. The geometric mean is often used when finding an average for numbers presented as percentages.
Arithmetic Mean - Simple average, equal to the sum of all values divided by the number of values.
Standard Deviation - A statistical measure of the historical volatility of a mutual fund or portfolio, usually computed using 36 monthly returns. More generally, a measure of the extent to which numbers are spread around their average.
S&P 500 - A market value weighted index comprised of 500 stocks of major companies selected by market size, industry, and liquidity
DJIA (Dow Jones Industrial Average) - A price-weighted average of 30 actively traded blue chip stocks. Widely used to gauge market performance.