In an experiment, a researcher gives some patients psychotherapy, gives others medication, and puts others on a waiting list. The researcher then measures how depressed the patients are feeling after six months. What is the independent variable in this experiment?

Question

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The independent variable in this experiment is the kind of treatment received by the patients. This is because the researcher is manipulating this variable by giving some patients psychotherapy, others medication, and putting others on a waiting list. The researcher is interested in whether this manipulation affects the dependent variable, which is the level of depression experienced by the patients after six months. The other options (number of patients and time span of six months) are not being manipulated by the researcher and are therefore not independent variables. Improvement in depression is the dependent variable, as it is the outcome being measured based on the manipulation of the independent variable.

In an Experiment, a Researcher Gives Some Patients Psychotherapy, Gives