Alpha equation - Meaning

The alpha of a fund is determined as follows: [ (sum of y) - ((b)(sum of x)) ] / n where: n =number of observations (36 months) x = rate of return for the S&P 500 b = beta of the fund y = rate of return for the fund American Depositary Receipts (ADRs) Certificates issued by a U.S. depositary bank, representing foreign shares held by the bank, usually by a branch or correspondent in the country of issue. One ADR may represent a portion of a foreign share, one share or a bundle of shares of a foreign corporation. If the ADR's are "sponsored," the corporation provides financial information and other assistance to the bank and may subsidize the administration of the ADRs. "Unsponsored"