In this edition I have added a chapter dealing with some elementary aspects of non-normal distributions, and have included a section of exercises at the end of each chapter. For the most part these exercises are direct applications of methods described in the text, but in a few places I have included a little additional discussion. The contexts of the exercises are intended to be realistic, but the ‘observations’ have been synthesized by computer; by this method an author has more control over the distributions he presents. As in the text, one or two slightly more theoretical exercises are marked with an asterisk.

I have not tried to make the exercises artificially easy; if experience in analysis is the key to statistical understanding, it is important that this experience should not lead to a false impression of what the discipline requires. There is therefore quite a lot of calculation needed in some exercises, and the reader will be wise to obtain the use of a good desk calculator. I believe that the day is still a little way off when the biologist learns his statistics with the help of one of the large computers, but he should certainly have the use of a modern desk machine.

I am very grateful for the many kind and helpful comments the first edition received and I have done my best to act on them.