Types of Correlation

1.Positive Correlation : When the values  of two variables move  in the  same direction .e.  when an increase in  the values  of one  variables  is associates with an increase in the values  the value of other  variable and a decrease in  the values of one variable is associated with  the decrease in  the values  of the other variable correlation is to be positive. For example  heights and weights  income and expenditure of a groups  of individuals prices and supply  of commodities.

2.Negative  Correlation: The values  of two  variables  move  in opposite  directions, so  that with  an increase  in the values  of one variable the value  of the other  variable  decrease and with a decrease in  the values of  one variable  the values of the  other variable increase, correlation is  said  to be negative. For example when  prices  increase demand  goes  down. Thus  there is   a negative correlation  between  these two  variables  i, e,  demand and supply.