Correlation

 

The stronger the comparison between the two sets of data, the stronger the correlation.  To see how strong the correlation is, draw a scattergram and see how close to a straight line the points lie:

 

If the points are scattered at random, there is no correlation.

 

        

 

The closer the points are to a straight line, the better the correlation.

 

                 

 

If the points make a straight line, there is perfect correlation.