Does a massage enable the muscles of tired athletes to recover from exertion faster than usual? To answer this question, researchers recruited eight amateur boxers to participate in an experiment. (British Journal of Sports Medicine, April 2000.) After a 10-minute workout in which each boxer threw 400 punches, half the boxers were given a 20-minute massage and half just rested for 20 minutes. Before they returned to the ring for a second workout, the heart rate (beats per minute) and blood lactate level (micromoles) were recorded for each boxer. The researchers found no difference in the means of the two groups of boxers for either variable.
a. Identify the data collection method used by the researchers.
b. Identify the experimental units of the study.
c. Identify the variables measured and their type (quantitative or qualitative).
d. What is the inference drawn from the analysis?
e. Comment on whether this inference can be made about all athletes.