Trend from 1961 - 1990 in the Karl - Knight
heat wave
index, which tracks the warmest
average minimum temperature over three consecutive nights in a year.
The Dow Jones Industrial
Average combines various stock prices to provide information about the health of the overall stock market; the Weather Channel reports «
heat indexes» that combine temperature and humidity to indicate how hot it feels; Consumer Reports measures product quality by combining measures across multiple dimensions; college football rankings are based on an
index that combines wins, losses, the quality of opponents, and other factors.