Understanding Variables in Controlled Experiments

In a controlled experiment, what is the role of the independent variable?

• It is the variable that is not included in the experiment.

• It is the variable that is changed or manipulated.

• It is the variable that is observed and measured.

• It is the variable that is kept constant.

In the example where students study for 15 minutes a night, what is the dependent variable?

• The number of students studying.

• The subjects the students are studying.

• The test grades of the students.

• The time of day the students study.

In the headache relief example, what is the independent variable?

• Whether or not aspirin is taken.

• The type of headache.

• The duration of the headache.

• The age of the person with the headache.

In the light bulb example, what is being measured as the dependent variable?

• The brand of the light bulb.

• The color of the light emitted.

• The number of hours the light bulb lasts.

• The cost of the light bulb.

Which part of a hypothesis does the dependent variable correspond to?

• The 'if' part of the hypothesis.

• The 'then' part of the hypothesis.

• The 'or' part of the hypothesis.

• The 'and' part of the hypothesis.