Multivariate data exploration and discrimination
Earlier chapters have made extensive use of exploratory graphs that have examined variables and their pairwise relationships, as a preliminary to regression modeling. Scatterplot matrices have been an important tool, and will be used in this chapter also. The focus will move from regression to methods that seek insight into the pattern presented by multiple variables. While the methodology has applications in a regression context, this is not a primary focus.
There are a number of methods that project the data on to a low-dimensional space, commonly two dimensions, suggesting “views” of the data ...