Advertising research: the independent variable is the element that is subject to arbitrary (not random) change, in order to test the results. For example: If the objective were to test audience response to headline copy, keeping all other factors equal, the sample audience would be subjected to different headline copy to determine the effectiveness of the various headlines. The audience response would be dependent on the stimulus provided-in this case the copy; therefore, the headline copy would be considered the independent variable when it came time to chart the results.
что, простите? может это поздний час, может ещё что-то, но я нихрена не врубила. кто хочет мне пояснить?