The contents of this chapter are described in most elementary textbooks on statistics. Many such books take a rather mathematical approach to the subject. It is often beneficial for the understanding to present statistical ideas and tools by practical examples. Statistics for Experimenters by Box, Hunter and Hunter  does so in a clear way and is probably one of the better statistics books available for people doing experimental work. Those readers who want to write programs for statistical analysis might consider Statistics – an introduction using R by Crawley . “R” is a freely available language and environment for statistical computing and graphics. It is platform independent and can be downloaded at http://cran.r-project.org/.