Question

what is the purpose of a control group in an experiment? to change the independent variable to serve as the experimental group to provide a standard for comparison to measure the dependent variable

Explanation:

In an experiment, a control group is a group that is not exposed to the independent variable. Its main purpose is to provide a baseline or standard against which the results of the experimental group (the group exposed to the independent variable) can be compared. Let's analyze each option:

• Option "To change the independent variable": The independent variable is manipulated by the experimenter, and the control group does not change it. So this is incorrect.
• Option "To serve as the experimental group": The control group and the experimental group are distinct; the control group is not the experimental group. So this is incorrect.
• Option "To provide a standard for comparison": This matches the purpose of a control group, as it allows us to see the effect of the independent variable by comparing the experimental group's results to the control group's (which has no manipulation of the independent variable).
• Option "To measure the dependent variable": Both the control and experimental groups can have the dependent variable measured, but that's not the purpose of the control group. The purpose is comparison, not just measurement. So this is incorrect.

Answer:

C. To provide a standard for comparison (assuming the orange option is labeled C; if the labels are different, adjust the identifier but keep the text "To provide a standard for comparison")