Pearson correlations summarize the linear pattern between two variables into a single number. This is very valuable, but it is useful to see the actual details of the pattern, and this can be done using a scatterplot. In Chapter 5, Visually Exploring the Data, one of the graphs described was a scatterplot, and once this type of plot is generated, it can be edited to add a fit line using the following dialog:
The default setting is to add a line for the linear fit, but other types of patterns can be fit as well if the pattern suggests they are more suited to the data. In the following chart, the linear fit line has been added along with the R2 value at the upper right:
The R2 value is equal to the square of the Pearson correlation. For these two fields, Percent_Urban and Secondary_School_Enrollment_Ratio_Males, the correlation is shown...
