Correlational research - Research Methodology - Manu Melwin Joy
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Transcript of Correlational research - Research Methodology - Manu Melwin Joy
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Manu Melwin JoyAssistant Professor
Ilahia School of Management Studies
Kerala, India.Phone – 9744551114
Mail – [email protected]
Correlational Research
• A correlation is simply
defined as a relationship
between two variables.
The whole purpose of
using correlations in
research is to figure out
which variables are
connected.
Correlational Research
• This simple definition is the
basis of several statistical
tests that result in
a correlation coefficient,
defined as a numerical
representation of the
strength and direction of a
relationship.
Correlational Research• Correlation research is looking
for variables that seem to
interact with each other, so
that when you can see one
changing, you have an idea of
how the other will change.
This often entails the
researcher using variables that
they can't control.
Direction of a Correlation• Positive Correlation: when two
variables go in the SAME
direction. For example,
domestic violence and
bowling. When bowling goes
up, so does domestic violence.
When domestic violence
decreases, so does bowling.
Direction of a Correlation• Negative Correlation: here the two
variables go in DIFFERENT directions.
For example, consumption of garlic
and dating (now I am making this one
up). The less garlic you eat, the more
you date. The more garlic you eat,
the less the date. One variable going
in one direction can be used to
predict the other variable going in the
opposite direction.
Correlational Coefficient• Scientists measure the strength
of a correlation by using a
number called a correlational
coefficient. Now you do not
have to know how they get the
number, but you should know
what it means when you see it.
The number range from -1 to
+1.
Correlational Coefficient• If two variables (like studying and
grades) have a correlation above
zero (like +.76) then you have a
positive correlation and the more
you study, the better grades you
have. The the number is below
zero (like -.42) then you have a
negative correlation and when
one variable goes up the other
goes down (like garlic and dating).
Correlational Coefficient• If two variables have a correlation
of zero then they have NO relationship with each other. The closer the numbers go to either +1 or -1, the stronger the correlation. The strength has nothing to do with whether the number is positive of negative. A correlation of -.88 is stronger than one that is +.56. the closer the number gets to zero (whether positive or negative), the weaker the correlation.
Limitations• It is very important to
remember that correlation doesn't imply causation and there is no way to determine or prove causation from a correlational study. This is a common mistake made by people in almost all spheres of life.
Limitations• For example, a US politician speaking
out against free lunches to poor kids at school argues -“You show me the school that has the highest free and reduced lunch, and I'll show you the worst test scores, folks” (nymag.com). This is a correlation he is speaking about - one cannot imply causation. The obvious explanation for this is a common cause of poverty: people who are too poor to feed their children will not have the best test scores.