Introduction

This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book presents mostly exploratory methods in which the raw data themselves. It describes methods for portraying the distribution of a single set of observations, for showing how the data spread out along the observation scale. The book explores methods for comparing the distributions of several data sets. It deals with paired measurements, or two-dimensional data; the graphical methods there help people probe the relationship and association between the two variables. The book also explains the same for measurements of more than two variables; an example of such multidimensional data is the heights, weights, blood pressures, pulse rates, and blood types of a group of people. It also presents methods for studying data in the context of statistical models and for plotting quantities derived from the data.