1.   Experimental designs always have an independent or cause variable present and a control group.

2.   If they fail to agree, it is necessary to Decide where some one has gone wrong, in experimental design or theory-making.

3.   It acknowledges the lack of control groups and neat experimental designs and works with perceived values of change.

4.   Studying the body clock for extended periods of time Consider the following experimental design for a volunteer studied on his own.

5.   This at once gave me the idea for the experimental design I wanted.

6.   By using these and other principles, which are embodied in the logic of experimental design, causal patterns could be determined empirically and theories built upon these.

7.   Essentially, the classic experimental design involves controlling all factors extraneous to the hypothesis of interest in order that this can be tested.