In a controlled experiment, ______________
A) you need only a single experimental organism which is tested again and again
B) the researcher has several hypotheses, one of which will be proven correct
C) the researcher knows the outcome before beginning the experiment
D) the researcher controls for the effects of all variables except one
E) the experimental organisms have all been used before and given good results

Question

Quizplus · Accepted Answer

In a controlled experiment, the researcher is attempting to isolate the effect of one variable on another by controlling for the effects of all variables except the one being tested. This means that choice D is the correct answer as it accurately reflects the process of a controlled experiment. In a controlled experiment, the researcher does not know the outcome beforehand, nor do they work from several hypotheses simultaneously. Additionally, the use of a single experimental organism is not a requirement, and the previous success of the experimental organisms is irrelevant.

In a Controlled Experiment, ______________