Question

Q: Analyze an experiment in which one group of plants receive extra fertilizer and another group receives extra water. Is the experiment controlled or uncontrolled? Support your answer.

My answer: The experiment is uncontrolled because there is no experiment used for comparison. If one of the plants is the experimental group, the other one has to be the control group. You can't add extra fertilizer in one plant and on the other you add extra water. That's an unctrolled group.

Answer 1

Please review it. I'm sure about my answer, but usually when Im sure, Im wrong.. and I think Im positive that it is correct.

Answer 2

You would want to say that there is no control group — one which receives neither extra water nor extra fertilizer. You can have more than one independent variable.

An <B>independent variable</B> is the potential stimulus or cause, usually directly manipulated by the experimenter, so it could also be called a manipulative variable.

A <B>dependent variable</B> is the response or measure of results.

<B>Extraneous variables</B> — other than the independent variable — potentially can affect the dependent variable, so they must be controlled. If possible, you try to keep them constant between the experimental and control group.

The <B>experimental group</B> receives the independent variable.

The <B>control group</B> is similar to experimental, except it does not receive the independent variable. Extraneous variables are balanced between experimental and control groups.