SITUATION
Inside a greenhouse, different trees are kept at three different humidity levels. These are left for three years. One tree is left outside in normal conditions. The heights of the trees are measured once a week.
ANSWER
Dependent Variables are the elements in the experiment which is not manipulated on purpose. It is usually the result of the investigation in which it depends on the change in the independent variables.
In the above scenario, the dependent variable is the: Height of the trees measured once a week.
Independent Variables, also known as manipulated variables, are the elements in the experiment that are changed or manipulated on purpose to test if the hypothesis is valid.
From the scenario, the independent variable is three different humidity levels.
Contròlled Variables are the elements that remain constant, unchanged, and not exposed to the independent group. Contròlled elements usually serve as the basis for comparing two different variables.
From the scenario, the contròlled variable is the tree left outside in a normal condition.
In summary:
Dependent variable: Height of the tree
Independent variable: 3 different levels of humidity
Contròlled variable: Tree left outside in a normal condition.
I hope it helps!
