Respuesta :
D. Kept the same to make an experiment a fair test.
‘a controlled variable’
‘a controlled variable’
A control variable Kept the same to make an experiment a fair test. Thus, option D is correct.
What Is a Control Variable ?
Variables may be controlled directly or indirectly by randomization methods.
A control variable is a type of variable unit which held constant in a research study.
It’s variability does not involve study aims but it is controlled and also show an influencing effect on the study outcomes.
It limits the effect of confounding and other extraneous variables and enhance the internal validity of a study.
In an experiment, the effect of an independent variable on a dependent variable can be investigated, for this control variables will help to understand that the results are caused by manipulated data in experiments.
Thus, option D is correct.
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