**Business / Finance / Beta Equation (Security):** The market beta of a security is determined as follows: Regress excess returns of stock y on excess returns of the market. The slope coefficient is beta. Define n as number of observation numbers. Beta = [(n) (sum of [xy]) ]-[ (sum of x) (sum of y)] / [(n) (sum of [xx]) ]-[ (sum of x) (sum of x)] where: n = # of observations (usually 36 to 60 months) x = rate of return for the S&P 500 index y = rate of return for the security

Science / Chemistry / Net Ionic Equation: A net ionic equation is an ionic equation with all DEFINE[spectator ions'>spectator ions eliminated. For example, Ag+(aq) + NO3-(aq) + Na+(aq) + Cl-(aq) = agcl(s) + Na+(aq) + NO3-(aq) is an ionic equa MORE

Entertainment / Video Games / Open Beta: A phase of testing for an online game (pre-release) where members of the public are invited to participate. MORE

Business / Finance / Portfolio Beta: Used in the context of general equities. The beta of a portfolio is the weighted sum of the individual asset betas, According to the proportions of the investments in the portfolio. E.g., if 50% of th MORE