A student is investigating the question "Which increases a person's breathing rate more after three minutes, lifting five-pouna

weights or lifting ten-pound weights?" She designs an experiment to test the question

Which is the dependent variable in her experiment?

breathing rate

weight lifted

duration of exercise

the person lifting weights

breathing rate

Explanation:

In an experimental design or research study, the independent variable is the variable that is being controlled or changed by the researcher in order to measure what changes or effect it has on the dependent variable. A change in the independent variable would bring about a change in the dependent variable. In order words, the dependent variable responds to the change in the independent variable.

In the student's experiment, we can easily see that the weight lifted is varied, and is controlled by the experimental, as it is expected to bring about a change in the breathing rate. In order words, the breathing rate is dependent on the weight lifted.

Therefore, breathing rate is the dependent variable in her experiment.