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.