correlation and correlation types...?
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Answer:
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Explanation:
In statistics, dependence or association is any statistical relationship, whether causal or not, between two random variables or bivariate data. In the broadest sense correlation is any statistical association, though it commonly refers to the degree to which a pair of variables are linearly related.
Usually, in statistics, we measure four types of correlations: Pearson correlation, Kendall rank correlation, Spearman correlation, and the Point-Biserial correlation. The software below allows you to very easily conduct a correlation.
Explanation:
Correlation is a relationship or dependence. It is the fact that two things or variables are so related that change in one is accompanied by a corresponding or parallel change in the other.”
According to Ferguson:
“Correlation is concerned with describing the degree of relation between two variables.”
According to Guilford:
“A coefficient of correlation is a single number that tells us to what extent two things are related, to what extent variation in one go with variations in the other.”
According to Lathrop:
“Correlation is a joint relationship between two variables.”
Types of Correlation:
1. Positive Correlation:
If the weight of an individual increases in proportion to increase in his height, the relation between this increase of height and weight is called as positive correlation. It ranges from 0 to + 1. If it is 0 then there is no relation at all. When it is + 1, then there is perfect positive correlation.
2. Negative Correlation:
It is just the opposite of positive correlation. If the weight of an individual does not increase in proportion to increase in his height or if the weight of an individual decreases with an increase in height, then it is said to be negative correlation, also ranges from 0 to -1. -1 is perfect negative correlation.
3. Zero Correlation:
Zero correlation is a correlation showing no relationship, or a correlation having a correlation coefficient of zero.
Importance of Correlation:
Correlation is very important in the field of Psychology and Education as a measure of relationship between test scores and other measures of performance. With the help of correlation, it is possible to have a correct idea of the working capacity of a person. With the help of it, it is also possible to have a knowledge of the various qualities of an individual.
After finding the correlation between the two qualities or different qualities of an individual, it is also possible to provide his vocational guidance. In order to provide educational guidance to a student in selection of his subjects of study, correlation is also helpful and necessary.
Methods of Finding Out the Correlation:
Various persons have suggested various methods for finding out correlation.
Two methods that are prevalent and important are:-
1. Rank order method.
2. Product Moment method.
Rank order Method:
Differences among individuals in many traits can often be expressed by ranking the subjects is 1 -2 – 3 order when such differences cannot be measured directly. For instance, individuals may be ranked in order of merit for obedience, industriousness, punctuality, honesty, salesmanship or social adjustment. Similarly various advertisements colour combinations, jokes and picture which are difficult to evaluate numerically may be put in order of merit for beauty, humour, artistic quality or some other quality.
The formula for calculating the correlation by Rank order method is as under:
P (rho) stands for coefficient of correlation from rank differences.
∑D2 represents the sum of the squares of differences in rank. N represents number of pairs.
In order to illustrate this formula, we give below an example:
So we can interpret the present result .2 by saying that there is negligible positive correlation.