Correlation Theory and Regression Analysis

Correlation Theory and Regression Analysis:

The term correlation deals with the relationship between two or more variables. If a change in one variable effect a change in other variable, the variables are said to be correlated.

There are basically three types of correlation, namely,

* Positive correlation
* Negative correlation
* Zero correlation.

In this Blog, let us also learn about Regression.

Regression Definition:

A regression is defined as a statistical analysis assessing the association between two variables. It is used to find the relationship between two variables.


Regression Formula:

Regression Equation(y) = a + bx
Slope(b) = (NΣXY - (ΣX)(ΣY)) / (NΣX2 - (ΣX)2)
Intercept(a) = (ΣY - b(ΣX)) / N

where
x and y are the variables.
b = the slope of the regression line
a = the intercept point of the line and the y axis.
N = Number of values or elements
X = First Score
Y = Second Score
ΣXY = Sum of the product of first and Second Scores
ΣX = Sum of First Scores
ΣY = Sum of Second Scores
ΣX 2 = Sum of square First Scores.

Correlation study are frequently used in psychology research to explain about relationships between the variables. There is a necessary relationship between two variables that can be study about correlation, one variable causes a change in another variable does not proved by finding a correlation relationship. we can study that no equal causation in correlation.

The Purpose of Correlation Study:

Correlation study used for the purpose of representing the relationships between variables. Correlation has three possible way of study: a negative correlation, a positive correlation and no correlation and no correlation. The measurement of correlation co-efficient of correlation strength and the range can be measured from –1 to +1.

*

Positive Correlations: Both variables are increase or decrease at the same time. A correlation coefficient nearer to +1 represents a strong positive correlation.
*

Negative Correlations: Indicates the increase in the amount of one variable, the other decreases (and vice versa). A correlation coefficient nearer to -1 represents a strong negative correlation.
*

No Correlation: It Indicates no relationships between two variables. The correlation coefficient of 0 represents no correlation.

Types of Correlation Study:

1. Naturalistic Observation:

Naturalistic observation explains about recording and observing the number of variables interested in the natural environment without manipulation or interference by the experimenter.

2. The Survey Method:

The most common methods for surveying and questionnaries used in psychological research. In this survey method, the participants can be selected by random sampling can complete a survey, test, or question that is related to variables of interest. Ensuring generalizability of survey results is one of the vital part for random sampling.

3. Archival Research:

Archival research can be performed by the method of analyzing study and this is conducted by researchers of other area or they looking for historical patient records.
Purpose

The correlation is a different way to measure how that is associated with two related variables. The research looks at things that already exist and determines if and in what way those things are related to each other. By doing correlations the purpose is to allow us to make a what we know about one variable based on prediction for another variable.

Hope you like the above example of Correlation Theory and Regression Analysis.Please leave your comments, if you have any doubts.