Introducción a La Estadistica

INTRODUCTORY BIOSTATISTICS

INTRODUCTORY BIOSTATISTICS

CHAP T. LE
Distinguished Professor of Biostatistics and Director of Biostatistics Comprehensive Cancer Center University of Minnesota

A JOHN WILEY & SONS PUBLICATION

Copyright 6 2003 by John Wiley & Sons, Inc. All rights reserved. Published by John Wiley & Sons, Inc., Hoboken, New Jersey. Published simultaneously in Canada. Nopart of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, scanning, or otherwise, except as permitted under Section 107 or 108 of the 1976 United States Copyright Act, without either the prior written permission of the Publisher, or authorization through payment of the appropriate per-copyfee to the Copyright Clearance Center, Inc., 222 Rosewood Drive, Danvers, MA 01923, 978-750-8400, fax 978-750-4470, or on the web at www.copyright.com. Requests to the Publisher for permission should be addressed to the Permissions Department, John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, (201) 748-6011, fax (201) 748-6008, e-mail: permreq@wiley.com. Limit of Liability/Disclaimerof Warranty: While the publisher and author have used their best e¤orts in preparing this book, they make no representations or warranties with respect to the accuracy or completeness of the contents of this book and specifically disclaim any implied warranties of merchantability or fitness for a particular purpose. No warranty may be created or extended by sales representatives or written salesmaterials. The advice and strategies contained herein may not be suitable for your situation. You should consult with a professional where appropriate. Neither the publisher nor author shall be liable for any loss of profit or any other commercial damages, including but not limited to special, incidental, consequential, or other damages. For general information on our other products and servicesplease contact our Customer Care Department within the U.S. at 877-762-2974, outside the U.S. at 317-572-3993 or fax 317-5724002. Wiley also publishes its books in a variety of electronic formats. Some content that appears in print, however, may not be available in electronic format. Library of Congress Cataloging-in-Publication Data Is Available ISBN 0-471-41816-1 Printed in the United States ofAmerica 10 9 8 7 6 5 4 3 2 1

To my wife, Minhha, and my daughters, Mina and Jenna with love

CONTENTS

Preface 1 Descriptive Methods for Categorical Data 1.1 Proportions, 1 1.1.1 Comparative Studies, 2 1.1.2 Screening Tests, 5 1.1.3 Displaying Proportions, 8 1.2 Rates, 11 1.2.1 Changes, 11 1.2.2 Measures of Morbidity and Mortality, 13 1.2.3 Standardization of Rates, 16 1.3 Ratios, 18 1.3.1Relative Risk, 19 1.3.2 Odds and Odds Ratio, 19 1.3.3 Generalized Odds for Ordered 2 Â k Tables, 22 1.3.4 Mantel–Haenszel Method, 26 1.3.5 Standardized Mortality Ratio, 30 1.4 Notes on Computations, 31 Exercises, 34 2 Descriptive Methods for Continuous Data 2.1 Tabular and Graphical Methods, 57 2.1.1 One-Way Scatter Plots, 57 2.1.2 Frequency Distribution, 58

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viiiCONTENTS

2.1.3 Histogram and the Frequency Polygon, 62 2.1.4 Cumulative Frequency Graph and Percentiles, 67 2.1.5 Stem-and-Leaf Diagrams, 70 2.2 Numerical Methods, 72 2.2.1 Mean, 73 2.2.2 Other Measures of Location, 76 2.2.3 Measures of Dispersion, 77 2.2.4 Box Plots, 80 2.3 Special Case of Binary Data, 81 2.4 Coe‰cients of Correlation, 83 2.4.1 Pearson’s Correlation Coe‰cient, 85 2.4.2 NonparametricCorrelation Coe‰cients, 88 2.5 Notes on Computations, 90 Exercises, 92 3 Probability and Probability Models 3.1 Probability, 108 3.1.1 Certainty of Uncertainty, 109 3.1.2 Probability, 109 3.1.3 Statistical Relationship, 111 3.1.4 Using Screening Tests, 115 3.1.5 Measuring Agreement, 118 3.2 Normal Distribution, 120 3.2.1 Shape of the Normal Curve, 120 3.2.2 Areas under the Standard Normal...