the correct IV or levels or DV in experimental hypotheses.

1. A group of college students were given a short course in speed-reading. The instructor was curious if a monetary incentive would influence performance on a reading assessment taken at the end of the course. Half the students were offered $5, and the other half were not offered money.
2. DMV researchers conducted a study, comparing drivers who listen to music while driving and drivers who don't listen to music while driving to determine if there is an effect on the number of traffic tickets received during the next two years.
3. The Society for the Care of Children (SCC) conducted a study that compared 10-year-olds with 8-year-olds regarding their attention span (in seconds) to a speech by the principal.
4. The history department wants to know which method of studying Russian history produces significantly higher exam scores. Thus, 20 students participated in a theatrical re-enactment the Siege of Leningrad in 1941 in class, and 20 students participated in a lecture about the Siege of Leningrad in 1941 by the professor. The following week, scores were obtained from a multiple-choice exam all 40 students took on the historical event.
5. Does marijuana really inhibits physical activity? Professor Nutig Finny selected 2 random samples of his adult students (after legal forms were properly signed). Sample 1 was given a joint to smoke and instructed to complete a 3-mile run. Sample 2 was given the fake joint and likewise instructed to complete a 3-mile run. The number of minutes to complete the run was recorded for each students afterwards. The results of this study were published in the Netherlands only.