Types of correlation | types and methods of correlation

Types of correlation :

 

1. Positive Correlation :

•  A positive correlation indicates a positive association between the variables
• The values of two variables are changing with same direction. The high numerical values of one variable relate to the high numerical values of the other. i.e. 0<r<1.
• For example, Height and weight, study time and grades.

 

2. Negative Correlation:

• Negative correlation indicate a negative association between the variables
• The values of variables change with opposite direction i.e. the high numerical values of the one variable relate to the low numerical values of the other. i.e. -1<r<0.
• For example, Price and quantity demanded, alcohol consumption and driving ability.

3. No Correlation: 

• There is no impact on one variable with an increase or decrease of values of another variable.
• If r=0 the two variables are uncorrelated. There is no linear relation between them.

4. Perfect Positive Correlation :

• When there is a change in one variable, and if there is equal proportion of change in the other variable say Y in the same direction, then these two variables are said to have a perfect positive Correlation i.e. r=1.

5. Perfectly Negative Correlation :

• Between two variables X and Y, if the change in X causes the same amount of change in Y in equal proportion but in opposite direction, then this correlation is called as perfectly Negative Correlation i.e. r=-1.
• If there is correlation between two numerical sets of data, positive or negative, the coefficient worked out can allow you to predict future trends between the two variables.