Question: 1. An investigator wants to predict a male adult's height from his length at birth. He obtains records of both measures from a sample of male military personnel.
2. An experimenter is interested in the effect of expectations and drugs on alertness. Each participant is given an amphetamine (stimulant) or a placebo (an inert substance). In addition, half in each group are told that the drug taken was a stimulant and half that the drug was a depressant. An alertness score for each participant is obtained from a composite of measures that included a questionnaire and observation.