In this chapter we analyse two sets of data using some of the methodology described in this book. Practical experience is important in the development of new statistical tools. Through such experience, strengths and weaknesses of methodology are exposed, and important directions for further research and development are discovered. Both for our sake and the reader’s, the examples in this chapter and other chapters in the book were not carefully selected to show off the tools described in this book. Rather, we required examples that show honestly the strengths of additive modelling as well the inherent difficulties.

In representing a realationship between a response and a number of independent variables, it is preferable when possible to work with a simple functional form in transformed variables rather than with a more complicated form in the original variables. This paper describes and illustrates a procedure to estimate appropriate transformations in this context.