Primer of Biostatistics

327 Pages·2011·19.58 MB·English

by  Stanton A. Glantz

Primer of Biostatistics
Notice
Medicine is an ever-changing science. As new research and clinical experience broaden
our knowledge, changes in treatment and drug therapy are required. The author and
the publisher of this work have checked with sources believed to be reliable in their
efforts to provide information that is complete and generally in accord with the
standards accepted at the time of publication. However, in view of the possibility of
human error or changes in medical sciences, neither the author nor the publisher
nor any other party who has been involved in the preparation or publication of this
work warrants that the information contained herein is in every respect accurate
or complete, and they disclaim all responsibility for any errors or omissions or for
the results obtained from use of the information contained in this work. Readers
are encouraged to confirm the information contained herein with other sources. For
example, and in particular, readers are advised to check the product information
sheet included in the package of each drug they plan to administer to be certain that
the information contained in this work is accurate and that changes have not been
made in the recommended dose or in the contraindications for administration. This
recommendation is of particular importance in connection with new or infrequently
used drugs.
Primer of Biostatistics
Seventh Edition
Stanton A. Glantz, PhD
Professor of Medicine
American Legacy Foundation Distinguished Professor in Tobacco Control
Director, Center for Tobacco Control Research and Education
Member, Cardiovascular Research Institute
Member, Philip R. Lee Institute for Health Policy Studies
Member, Helen Diller Family Comprehensive Cancer Center
University of California, San Francisco
San Francisco, California
New York Chicago San Francisco Lisbon London Madrid Mexico City
Milan New Delhi San Juan Seoul Singapore Sydney Toronto
Copyright © 2012 by The McGraw-Hill Companies, Inc. All rights reserved. Except as permitted under the United States Copyright Act of 1976,
no part of this publication may be reproduced or distributed in any form or by any means, or stored in a database or retrieval system, without
the prior written permission of the publisher.
ISBN: 978-0-07-179440-4
MHID: 0-07-179440-9
The material in this eBook also appears in the print version of this title: ISBN: 978-0-07-178150-3,
MHID: 0-07-178150-1.
All trademarks are trademarks of their respective owners. Rather than put a trademark symbol after every occurrence of a trademarked name,
we use names in an editorial fashion only, and to the benefi t of the trademark owner, with no intention of infringement of the trademark. Where
such designations appear in this book, they have been printed with initial caps.
McGraw-Hill eBooks are available at special quantity discounts to use as premiums and sales promotions, or for use in corporate training
programs. To contact a representative please e-mail us at [email protected].
Previous editions copyright © 2005, 2002, 1997, 1992, 1987, 1981 by The McGraw-Hill Companies, Inc.
TERMS OF USE
This is a copyrighted work and The McGraw-Hill Companies, Inc. (“McGraw-Hill”) and its licensors reserve all rights in and to the work.
Use of this work is subject to these terms. Except as permitted under the Copyright Act of 1976 and the right to store and retrieve one copy of
the work, you may not decompile, disassemble, reverse engineer, reproduce, modify, create derivative works based upon, transmit, distribute,
disseminate, sell, publish or sublicense the work or any part of it without McGraw-Hill’s prior consent. You may use the work for your own
noncommercial and personal use; any other use of the work is strictly prohibited. Your right to use the work may be terminated if you fail to
comply with these terms.
THE WORK IS PROVIDED “AS IS.” McGRAW-HILL AND ITS LICENSORS MAKE NO GUARANTEES OR WARRANTIES AS
TO THE ACCURACY, ADEQUACY OR COMPLETENESS OF OR RESULTS TO BE OBTAINED FROM USING THE WORK,
INCLUDING ANY INFORMATION THAT CAN BE ACCESSED THROUGH THE WORK VIA HYPERLINK OR OTHERWISE, AND
EXPRESSLY DISCLAIM ANY WARRANTY, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. McGraw-Hill and its licensors do not warrant or guarantee that the
functions contained in the work will meet your requirements or that its operation will be uninterrupted or error free. Neither McGraw-Hill nor
its licensors shall be liable to you or anyone else for any inaccuracy, error or omission, regardless of cause, in the work or for any damages
resulting therefrom. McGraw-Hill has no responsibility for the content of any information accessed through the work. Under no circumstances
shall McGraw-Hill and/or its licensors be liable for any indirect, incidental, special, punitive, consequential or similar damages that result from
the use of or inability to use the work, even if any of them has been advised of the possibility of such damages. This limitation of liability shall
apply to any claim or cause whatsoever whether such claim or cause arises in contract, tort or otherwise.
To Marsha Kramar Glantz
This page intentionally left blank
What I’ve proposed is that we have a panel of medical experts that are making determina-
tions about what protocols are appropriate for what diseases. There’s going to be some
disagreement, but if there’s broad agreement that, in this situation the blue pill works better
than the red pill, and it turns out the blue pills are half as expensive as the red pill, then we
want to make sure that doctors and patients have that information available to them.
President Barack Obama, 2009*
*Interview with ABC News’ Dr. Timothy Johnson, July 15, 2009.
This page intentionally left blank
Contents
Preface ...........................................................xiii 4. The Special Case of Two Groups:
The t test .................................................49
1. Biostatistics and Clinical Practice ................1
The General Approach .....................................49
What Do Statistical Procedures Tell You? ............3 The Standard Deviation of a Difference
Why Not Just Depend on the Journals? ...............4 or a Sum ....................................................51
Why Has the Problem Persisted? ........................5 Use of t to test Hypotheses About
Two Groups .................................................52
2. How to Summarize Data .............................7
What if the Two Samples Are Not
Three Kinds of Data ..........................................7 the Same Size? ..........................................56
The Mean .........................................................9 Cell Phones Revisited ......................................56
Measures of Variability ......................................9 The t test is an Analysis of Variance ...................59
The Normal Distribution ...................................10 Common Errors in the Use of the t test
Getting the Data .............................................10 and How to Compensate for Them ................60
Random Sampling .......................................10 How to Use t tests to Isolate Differences
Bias ...........................................................12 Between Groups in Analysis of Variance ........62
Experiments and Observational Studies ........13 The Bonferroni t test ...................................62
Randomized Clinical Trials............................14 More on Cell Phones and Rabbit Sperm ........63
How to Estimate the Mean and Standard A Better Approach to Multiple Comparisons:
Deviation from a Sample ...............................15 The Holm t test .......................................64
How Good Are These Estimates? ......................15 The Holm-Sidak t test ..................................65
Percentiles .....................................................19 Multiple Comparisons Against
Pain Associated with Diabetic Neuropathy .....23 a Single Control ..........................................67
Summary ........................................................25 The Meaning of P .....................................................67
Problems ........................................................25 Statistical Versus Real (Clinical) Thinking ......69
Why P < .05? ..............................................70
3. How to Test for Differences between
Problems ........................................................71
Groups ....................................................27
5. How to Analyze Rates and Proportions .......73
The General Approach .....................................27
Two Different Estimates of the Back to Mars ..................................................73
Population Variance .....................................31 Estimating Proportions from Samples ...............75
What is a “Big” F? ...........................................34 Hypothesis Tests for Proportions .......................78
Cell Phones and Sperm ...................................38 The Yates Correction for Continuity ...............79
An Early Study.............................................38 Effect of Counseling on End-of-Life
A Better Control Group.................................40 Planning in Homeless People ...................79
An Experimental Study .................................41 Another Approach to Testing Nominal Data:
Unequal Sample Size ......................................41 Analysis of Contingency Tables .....................80
Two Way Analysis of Variance ...........................44 The Chi-Square Test Statistic .......................81
Problems ........................................................44 The Yates Correction for Continuity ...............84
ix