Dow Jones Industrial Average
This is the best known U.S.index of stocks. It contains 30 stocks that trade on the New York stock exchange. The Dow, as it is called, is a barometer of how shares of the largest U.S.companies are performing. The Dow originally was a true average: add the value of the 30 stocks in the Index and divide by 30. Though it is called an average, it now serves as more of an index. The Dow is computed by adding the total value of the 30 stocks and dividing by a factor that adjusts the distortions caused by stock splits over the years. As of Oct. 24, 1996, the factor was 0.33539933.