P. Armitage

One frequently encounters data consisting of a series of proportions, occurring in groups which fall into some natural order. The question usually asked is then not so much whether the proportions differ significantly, but whether they show a significant trend, upwards or downwards, with the ordering of the groups, In the data shown in Table 1, for, instance, the usual test for a 2 X 3 contingency table yields a x2 equal to 7.89 on 2 degrees of freedom, corresponding to a probability of about 0.02. But this calculation takes no account of the fact that the carrier rate increases with the tonsil size, and it is reasonable to believe that a test specifically designed to detect a trend in the carrier rate as the tonsil size increases would show a much higher degree of significance.

The explanation and implementation of statistical methods for the medical researcher or statistician remains an integral part of modern medical research. This book explains the use of experimental and analytical biostatistics systems. Its accessible style allows it to be used by the non-mathematician as a fundamental component of successful research.
\n
\nSince the third edition, there have been many developments in statistical techniques. The fourth edition provides the medical statistician with an accessible guide to these techniques and to reflect the extent of their usage in medical research.
\n
\n
\nThe new edition takes a much more comprehensive approach to its subject. There has been a radical reorganization of the text to improve the continuity and cohesion of the presentation and to extend the scope by covering many new ideas now being introduced into the analysis of medical research data. The authors have tried to maintain the modest level of mathematical exposition that characterized the earlier editions, essentially confining the mathematics to the statement of algebraic formulae rather than pursuing mathematical proofs.