The line of best fit for the scatter graph would look like this: Interpolation and extrapolationДЇrom the diagram above, we can estimate how many umbrellas would be sold for different amounts of rainfall. It should also follow the same steepness of the crosses. Lines of best fitДЄ line of best fit is a sensible straight line that goes as centrally as possible through the coordinates plotted. No correlation means there is no connection between the two variables. Negative correlation means as one variable increases, the other variable decreases. Positive correlation means as one variable increases, so does the other variable. Graphs can either have positive correlation, negative correlation or no correlation. If data plotted on a scatter graph shows correlation, we cannot assume that the increase in one of the sets of data caused the increase or decrease in the other set of data вЂ“ it might be coincidence or there may be some other cause that the two sets of data are related to. However, it is important to remember that correlation does not imply causation. On days with higher rainfall, there were a larger number of umbrellas sold. The graph shows that there is a positive correlation between the number of umbrellas sold and the amount of rainfall. The number of umbrellas sold and the amount of rainfall on 9 days is shown on the scatter graph and in the table. Scatter graphs are a good way of displaying two sets of data to see if there is a correlation, or connection.

Scatter plot correlation