Question

1. what is the purpose of a control group in an experiment? to introduce a new variable to ensure the results are due to the independent variable to test multiple hypotheses at once to vary the experimental conditions

Explanation:

A control group in an experiment is used to provide a baseline for comparison. It does not receive the independent variable treatment. By comparing the experimental group (which receives the independent variable) to the control group, we can determine if the changes in the dependent variable are due to the independent variable (since other factors are kept constant between the two groups).

• "To introduce a new variable" is incorrect because the control group is meant to keep variables constant, not introduce new ones.
• "To test multiple hypotheses at once" is not the purpose of a control group; a control group is for isolating the effect of one independent variable.
• "To vary the experimental conditions" is incorrect as the control group has constant conditions (except for the independent variable) to compare with the experimental group.
• "To ensure the results are due to the independent variable" is correct because the control group helps rule out other factors, so any differences between the experimental and control groups can be attributed to the independent variable.

Answer:

B. To ensure the results are due to the independent variable