Dr. Branch would like to study the relationship between room lighting and college students' test performance. He randomly assigns college students to two groups. The first group takes an exam in a dimly lit room and the second group takes the same exam in a regularly lit room. What is the independent variable?

The independent variable is the lighting intensity.

When you want to check the influence of one phenomenon on another, it is necessary to use two variables. A dependent variable and another independent variable.

With these two types of variables, it is possible to know the influence of one (independent) variable on another (dependent).

For example, the independent variable in the situation presented is light intensity. This variable will influence the result obtained in the dependent variable, that is, the performance of students on tests.

While the dependent variable represents different results (it changes depending on the independent variable), the independent variable does not change as a result of other variables.

According to the above, it can be inferred that the independent variable that Dr. Branch is using is the lightning intensity.

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answer; i believe the correct answer is (a) the correlation between the cause variable and outcome variable is zero;