Types of correlation
Positive correlation
If there is a correlation between two sets of data, it means they are connected in some way.
As the temperature increases, the number of ice-creams sold increases. The results are approximately in a straight line, with a positive gradient. Therefore there is a positive correlation.
Negative correlation
This scattergraph shows the connection between the number of weeks a song has been in the Top 40 and sales of the single for that week.
There is a definite connection between the two sets of data, as the results are approximately in a straight line.
As the number of weeks increases, sales decrease. The line has a negative gradient and therefore a negative correlation.
No correlation
The following scatter diagram shows the connection between a person's house number and their IQ (one measure of intelligence).
There is no connection between these values and this is shown by the scattergraph.
