This book is an exposition of statistical methodology that focuses on ideas and concepts, and makes extensive use of graphical presentation. It avoids, as much as possible, the use of mathematical symbolism. It is particularly aimed at scientists who wish to do statistical analyses on their own data, preferably with reference as necessary to professional statistical advice. It is intended to complement more mathematically oriented accounts of statistical methodology. It may be used to give students with a more specialist statistical interest exposure to practical data analysis.

While no prior knowledge of specific statistical methods or theory is assumed, there is a demand that readers bring with them, or quickly acquire, some modest level of statistical sophistication. Readers should have some prior exposure to statistical methodology, some prior experience of working with real data, and be comfortable with the typing of analysis commands into the computer console. Some prior familiarity with regression and with analysis of variance will be helpful.

We cover a range of topics that are important for many different areas of statistical application. As is inevitable in a book that has this broad focus, there will be investigators working in specific areas – perhaps epidemiology, or psychology, or sociology, or ecology – who will regret the omission of some methodologies that they find important.

We comment extensively on analysis results, noting inferences that seem well-founded, and noting limitations on inferences that can be drawn. We emphasize the use of graphs for gaining insight into data – in advance of any formal analysis, for understanding the analysis, and for presenting analysis results.