The following are the main properties of correlation.
1. Coefficient of Correlation lies between -1 and +1:
The coefficient of correlation cannot take value less than -1 or more than one +1. Symbolically,
-1<=r<= + 1 or | r | <1.
2. Coefficients of Correlation are independent of Change of Origin:
This property reveals that if we subtract any constant from all the values of X and Y, it will not affect the coefficient of correlation.
3. Coefficients of Correlation possess the property of symmetry:
The degree of relationship between two variables is symmetric as shown below:
4. Coefficient of Correlation is independent of Change of Scale:
This property reveals that if we divide or multiply all the values of X and Y, it will not affect the coefficient of correlation.
5. Co-efficient of correlation measures only linear correlation between X and Y.
6. If two variables X and Y are independent, coefficient of correlation between them will be zero.
Plot different sets of values i.e. (8, 70), (16, 58) (24, 50), (31, 32), (42, 26), (50, 12) on the graph paper. Join these points. The result is the scatter diagram. This data gives high degree of negative correlation.