The Dow Jones Industrial Average is computed by 1) adding the prices of 30 large "blue-chip" stocks and dividing by 30 2) calculating the total market value of the 30 firms in the index and dividing by 30 O 3) adding the prices of the 30 stocks in the index and dividing by a divisor 4) adding the prices of the 500 stocks in the index and dividing by a divisor