The answer is "room color is independent variable".
The two principle variables in an examination are the independent and dependent variable.
An independent variable is the variable that is changed or controlled in a logical trial to test the impacts on the dependent variable.
A dependent variable is the variable being tried and estimated in a logical test.
The independent and ward factors might be seen regarding circumstances and end results. In the event that the independent variable is changed, at that point an impact is found in the dependent variable.
Thus, in the given case, room color is independent variable.