Generations of biologists have relied upon this useful book, which presents the basic concepts of statistics so lucidly and convincingly. It recognises that students must be aware of when to use standard techniques and how to apply the results they obtain. Since many biologists do not have a strong mathematical background, the arguments are gauged in terms which can be easily understood by those with only an elementary knowledge of algebra. Mathematical derivations are avoided and formulae are only used as a convenient shorthand. Although the subject is presented with great simplicity, the coverage is wide and will satisfy the needs of those working in many disciplines. New material for this third edition includes consideration of pocket electronic calculators, and a special chapter is devoted to a discussion of the problems associated with numerical calculation, electronic calculators and computers.