A researcher claims that the mean resting pulse rate of all college basketball players in the United States is less than the mean resting pulse rate of all professional basketball players in the United States. The resting pulse rates of a random sample of 115 college basketball players were measured as were the resting pulse rates of a random sample of 80 professional basketball players. The mean resting pulse rates of the two groups were compared.
In this study, the explanatory variable is
A) the level of basketball played (college or professional).
B) the number of players studied in each group.
C) the resting pulse rate.
D) confounded with the placebo effect.

Question

Quizplus · Accepted Answer

The explanatory variable in this study is the level of basketball played (college or professional) as it is the factor that is believed to impact the resting pulse rate. The number of players studied in each group is not the explanatory variable, but rather a variable that affects the precision of the estimate. The resting pulse rate is the response variable of interest. The placebo effect is not relevant to this study.

A Researcher Claims That the Mean Resting Pulse Rate of All