Dependent and Independent Variable
We can seperate dependent and independent variable in this way.
Dependent variable means it”s change depends on the independent variable.
For example, if we “re having an experiment to find out the relationship between light intensity and the rate of photosynthesis.Obviously,the rate of photosynthesis depend on the change of light intensity.Therefore, we can say that light intensity is the independent variable.
Also,we can determine which is dependent or independent variable in an other way.According to the above example, between light intensity and rate of photosynthesis,we can alter only the light intensity.Therefore, the factor that we can change by ourselves in an experiment is called independent variable.
Abot the control variable, it is factors which we need to keep them constant to ensure the minimum error during the experiment.For the above exampe, light intensity is a main factor that we want to find out its relationship with rate of photosynthesis.Therefore, It won”t be a control variable.Then, other factors which will affect the rate of photosynthesis such as humidity, temperature and CO2 concentration are the control variable.Since they must be constant, and the light intensity is the only variable in the above experiment .If a change in output leads to a change in the amount of a factor, it is a variable factor. Else, it is a fixed factor.
e.g. 1
Suppose a firm employs 2 units of labour while the output is 10/unit of labour.
Now, if the output increases to 15/unit of labour but the number of labour drops to 1, then labour is still a variable factor. It is because the rise in output leads to a drop in number of labour. The drop of labour may be explained by the fact that the firm wants to raise capital (or other reasons).