Can You Give Me An Example Of Control Variable In Any Kind Of Research?


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Iris Phillips Profile
Iris Phillips answered
Control variables in an experiment are the variables which are required to remain constant. An example of control variables can be found in research into the growth of micro bacteria in varying growth solutions. Control variables here are constant temperature, constant amount of light and the same amount and type of micro bacteria for each solution.

  • Types of variables
Every type of scientific research has three different types of variables. These are the control variables, the independent variables and the dependent variables. In the above example, for instance, the independent variable would be the different solutions representing the growth medium.

The dependent variable is the growth measured either at certain intervals or at the end of a specific period of time, another constant for all solutions and therefore another control variable.

  • Other examples of control variables
In a study to find out how many 14 year old pupils like to study mathematics, the control variables would be the age of the students and the question itself.

Independent variables would be the gender of each pupil interviewed and their personal opinion. The dependent variable is the outcome of the survey.

A survey on how a new tax law is being received in various parts of a country would have the the law as the control variable; gender, age and location as independent variables and the outcome is again the dependent variable.

Research on how an insecticide may affect plants would assume control variables of pot size, soil, light, temperature and amount and type of insecticide applied. The independent variable is represented by varying plant types, the effects are the dependent variable.

Control variables play an important role in research of any kind. They provide common factors without which it would be impossible to draw valid conclusions out of the comparison of results.
Anonymous Profile
Anonymous answered
If one were to measure the influence of different quantities of fertiliser on the plant growth, examples of control variables that would need to be kept constant include the type of plant, the type of fertiliser, the amount of sunlight the plant gets, the size of the pots.

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