Question

Arthur reads an article describing an experiment to test the effects of caffeine on the reaction time of humans—how long it took them to respond to a particular signal. In the experiment, the subjects' reaction times were measured, then they were divided into three groups. One group was given a high dose of caffeine. The second group was given a medium dose of caffeine. The third group was given a sugar pill that had no caffeine. After waiting 45 min for the caffeine to take effect, the reaction times were measured again. In the experiment Arthur read about, what was the outcome variable (dependent variable)? A. the change in reaction times for each person B. the amount of caffeine given to each person C. the amount of time the caffeine was given to take effect D. the type of signal each person responded to

Answer 1

A. the change in reaction times for each person

Answer 2

Answer: A. the change in reaction times for each person

Step-by-step explanation:

In an experiment the dependent or experimental variable is the one which changes because of the impact of changes on the independent variable. The independent variable is the one which can be changed or manipulated in an experiment. It exerts it's effects over the dependent variable.

The coffee here is the independent variable. The third group with sugar pill and no coffee can be considered as control group. The change in the reaction times for each person is the dependent variable because it changes due to the intake of coffee.