Simple Graph

The values of the two variables are plotted on a graph paper. We get two curves one for x variables and another for y  variables. These  two curves reveal the direction and  closeness  of the two  curves and  also reveal whether or not the variables  are related. If  both the  curves move in  the same  direction i, e,  parallel to each other either upward  or downward  correlation is said  to be positive. On the other hand  if they move in  opposite  directions then the  correlation  is said  to be negative .

The above  methods is used  in the case  of time  series. This methods  also does  not reveal  the  extent to  which the variables  are related.