Experimental Design

Experimental Design - Experimental Design Scientists often...

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Experimental Design Scientists often perform experiments by doing some sort of a manipulation. In the example above, one group of mice was given a hormone and the other group was not. The group of mice that was not given the hormone is referred to as a control group. A control serves for comparison. If the average weight of the control mice had been the same as that of the group given the hormone, it would be necessary to conclude that the hormone did not cause a change in growth. Many experiments are controlled as described above. A controlled experiment is not one in which variables are controlled, it is usually not possible to control all of the factors that may affect the outcome of an experiment. In a controlled experiment, the control group experiences the same environment as the experimental (manipulated) group. If an environmental variable affects the experimental group, it also affects the control group equally. In the example above, the researcher wanted to determine if a hormone caused mice to grow larger. It is possible that
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This note was uploaded on 11/10/2011 for the course BIOLOGY bi 101 taught by Professor - during the Fall '10 term at Montgomery.

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Experimental Design - Experimental Design Scientists often...

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