An experiment is performed to determine if eating breakfast affects students' performance on exams. The experimental (independent) variable is
A. the students' scores on the exams.
B. the ages of the students.
C. whether or not the students eat breakfast.
D. whether or not the students drink coffee.

The experimental (independent) variable is whether or not the students eat breakfast (Option C).

The independent variable is the variable that does not change during an experimental procedure, which is manipulated by the researcher.Conversely, the dependent variable is the variable being tested or measured in an experiment, which is 'dependent' on the independent variable.In consequence, the independent variable is said to be the cause, whereas the dependent variable is said to be the effect whose value fluctuates depending on the change produced in the independent variable.

In conclusion, the experimental (independent) variable is whether or not the students eat breakfast (Option C).

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