Coefficient of correlation is calculated to find:
|A||Value of other variable if the value of one variable is known|
|B||Whether there is significant association between two variables|
|C||Difference between two proportions|
Ref: High Yield Biostatistics, Pg: 47
Coefficient of correlation is calculated to establish or rule out the presence of significant association between two variables. It is used to measure the strength and the direction of association.
Correlation coefficient (r) is the measure of correlation. It varies from –1 to +1. These two values describe a perfect negative and positive linear relationship between two variables. r = 0 implies that there’s no linear relationship.