Power Analysis For Experimental Research: A Practical Guide For The Biological, Medical And Social Sciences

This page intentionally left blank Power Analysis for Experimental Research A Practical Guide for the Biological, Medical and Social Sciences Power analysis is an essential tool for determining whether a statistically significant result can be expected in a scientific experiment prior to the experiment being performed. Many funding agencies and Institutional Review Boards now require power analyses to be carried out before they will approve experiments, particularly where they involve the use of human subjects. This comprehensive, yet accessible, book provides practicing researchers with step-by-step instructions for conducting power/ sample size analyses, assuming only basic prior knowledge of summary statistics and the normal distribution. It contains a unified approach to statistical power analysis, with numerous easy-to-use tables to guide the reader without the need for further calculations or statistical expertise. This will be an indispensable text for researchers and graduates in the medical and biological sciences needing to apply power analysis in the design of their experiments. .     is Professor at the University of Maryland School of Medicine and Director of Research of the Complementary Medicine Program. He has served as the editor-in-chief of the peer-reviewed methodology journal Evaluation and the Health Professions for the past 25 years and has conducted statistical research in a number of disciplines related to the medical sciences. -  is a Data Analyst at the Department of Veteran’s Affairs, Puget Sound Health Care System in Seattle, Washington. She previously worked as a statistical consultant with a particular interest in metaanalysis. Power Analysis for Experimental Research A Practical Guide for the Biological, Medical and Social Sciences R. BARKER BAUSELL YU-FANG LI    Cambridge, New York, Melbourne, Madrid, Cape Town, Singapore, São Paulo Cambridge University Press The Edinburgh Building, Cambridge  , United Kingdom Published in the United States of America by Cambridge University Press, New York www.cambridge.org Information on this title: www.cambridge.org/9780521809160 © Bausell and Li 2002 This book is in copyright. Subject to statutory exception and to the provision of relevant collective licensing agreements, no reproduction of any part may take place without the written permission of Cambridge University Press. First published in print format 2002 - isbn-13 978-0-511-07249-9 eBook (EBL) -  eBook (EBL) isbn-10 0-511-07249-X - isbn-13 978-0-521-80916-0 hardback - isbn-10 0-521-80916-9 hardback Cambridge University Press has no responsibility for the persistence or accuracy of s for external or third-party internet websites referred to in this book, and does not guarantee that any content on such websites is, or will remain, accurate or appropriate. This book is dedicated to Jesse Turner Bausell Contents Introduction 1 The conceptual underpinnings of statistical power page ix 1 2 Strategies for increasing statistical power 16 3 General guidelines for conducting a power analysis 36 4 The t-test for independent samples