ABSTRACT
In these plots we are looking for a linear relationship between the two variables which is summarized by the spread and scatter of points. If one variable is linearly related to the other, then as one variable changes, the other will change in proportion and the points will tend to fall on a straight line. The size of a Pearson correlation coefficient indicates the degree to which the points in a scatter diagram tend to fall along a straight line (summarizes the linear relationship). The value of the Pearson correlation coefficient, can range between −1 to +1, in both cases this would indicate a perfect linear relationship. The Pearson correlation is used when the underlying data distribution is normal (see Chapter 8).
