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variable-Its any item, factor, or condition that can be controlled or changed
The following are three types of variables.
Controlled variables are quantities that a scientist wants to remain constant, and he must observe them as carefully as the dependent variables. For example, if we want to measure how much water flow increases when we open a faucet, it is important to make sure that the water pressure (the controlled variable) is held constant.
Dependent Variable- variable that is not under the experimenter's control -- the data. It is the variable that is observed and measured in response to the independent variable for example income depends on years of education.
Independent Variable (manipulated) - Its a variable which purposely changes or varies over the course of the investigation for example age.
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