Differentiate between Correlational and Experimental Method.
Difference between Correlational and Experimental Method:
As the name implies, the researcher looks to establish relationships between two variables. He makes a premise that two variables may be related in some way and then measure the value of both under different circumstances to test his hypothesis if indeed there is a relation between the two variables. The next logical step is to check if this relationship has any statistical significance.
In correlational research, there is no attempt made by the researcher to influence the variables. The researcher merely records the values of the variables and then tries to establish some sort of relationship between the variables.
It has to be understood that correlational research does not try to establish cause and effect relationship between variables. The researcher does not manipulate variables, and he does not make any statement of cause and effect in any correlational research.
So, though scientists have known for long that, in people with clinical depression, there have been found low levels of neurotransmitters such as serotonin and norepinephrine, they do not point to a causal relationship between depression and low levels of neurotransmitters.
Experimental research is what most people consider being more scientific though non experimental does not mean that the research is unscientific by any means. It is human nature to try to find out what happens when changes are introduced in variables.
Thus, taking up the previous example of blood pressure and cholesterol, a research can deliberately increase the blood pressure of a subject and then record his cholesterol levels to see if there is any increase or decrease. If changes induced in a variable lead to changes in another variable, a researcher is in a position to say that there is a causal relationship between the two variables.
Following are the differences between Correlational and Experimental Research:
It is only experimental research that can establish a causal relationship between variables.
In correlational research, there is no attempt made by the researcher to control or influence variables. He merely records the values of variables. Correlational research can establish a correlation between two variables without stating causal relationship. So, even though scientists know that in most cases of clinical depression people have been found with low levels of neurotransmitters like serotonin and epinephrine, they do not make a causal relationship that low levels of neurotransmitters are responsible for depression in people.