A controlled experiment is a scientific test done under controlled conditions, meaning that just one (or a few) factors are changed at a time, while all others are kept constant.

In a controlled experiment, we assign people or things to groups and apply some treatment to one of the groups, while the other group does not receive the treatment.

All other factors that could have an effect on the outcome of the experiment must be controlled or held constant. In addition, one group in the experiment should be a control group, a designated group …

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Test your knowledge on the scientific method and experimental design!

To avoid errors, researchers may randomly divide subjects into control and experimental groups. Both groups should receive a treatment, like a pill (real or placebo), to counteract the placebo effect.

Normal students, randomly assigned as prisoners or guards, adopted their roles to alarming extents. Despite knowing it was an experiment, guards enforced harsh control, while prisoners exhibited …

Independent variable An independent variable is a variable that represents a quantity that is being manipulated in an experiment. x is often the variable used to represent the independent variable in …

Perhaps most importantly, Neurospora cells could be grown in the lab on simple medium (nutrient broth or gel) whose chemical composition was 100% known and controlled by the experimenter.

To test the hypothesis, we need to make an observation or perform an experiment associated with the prediction. For instance, in this case, we would plug the toaster into a different outlet and see if it toasts.