1. Coefficient of correlation is a measure of strength of linear correlation between two variables, but it gives no indication about presence of cause and effect relationship between them.
2. Sometimes there is no correlation between two variables even though due to presence of other factors, the value of | r | may be near to 1.
3. When r = 0, we can say that there is lack of linear correlation. But there may be non-linear relationship between them.
4. The bivariate data obtained for a given region or class or given time duration, then correlation coefficient computed for such data, its interpretation should be limited to such data only otherwise it leads to misunderstanding.
