We have 38 subjects (people) for an experiment. We play music with lyrics for each of the 38 subjects. During the music, we have the subjects play a memorization game where they study a list of 25 common five-letter words for 90 seconds. Then, the students will write down as many of the words they can remember. We also have the same 38 subjects listen to music without lyrics while they study a separate list of 25 common five-letter words for 90 seconds, and write down as many as they remember. This is an example of: ____________
