ABSTRACT
This chapter presents the some concepts, notation and considers simple regression. It organizes into three parts, first, graphs for exploring the raw data before any serious regression analysis is done, to help understand peculiarities and potential difficulties with the particular set of data and to suggest models. Second, graphs for use during the analysis, after some intermediate stages of regression have been carried out, to examine components of the fit and suggest modifications to the model. Third, graphs to be employed after the model has been fit, to assess the quality of the fit and to diagnose deviations from the model assumptions. The chapter discusses the main ideas of two examples. The first is a set of data taken from a survey of telephone cable splicing work. The second example is taken from Davies. Thirty rubber specimens were rubbed with an abrasive material and the amount of material rubbed off, the abrasion loss, was related to hardness and tensile strength.
