INTRODUCTION TO BIOSTATISTICS AND RESEARCH METHODS

Fifth EditionINTRODUCTION TOBIOSTATISTICSAND RESEARCHMETHODSP.S.S. Sundar RaoJ. Richard

Introduction to Biostatisticsand Research MethodsFifth EditionP.S.S. Sundar Rao, Dr. PH.Research Coordinator, The Leprosy Mission Trust IndiaNew DelhiFormer Director, Schieffelin Leprosy Research and Training CentreKarigiri, Tamil NaduJ. Richard, Ph.D.Consultant, Biostatistics and Research MethodsFormer Professor and Head, Department of BiostatisticsChristian Medical College, VelloreNew Delhi-1100012012

INTRODUCTION TO BIOSTATISTICS AND RESEARCH METHODS, Fifth EditionP.S.S. Sundar Rao and J. Richard 2012 by PHI Learning Private Limited, New Delhi. All rights reserved. No part ofthis book may be reproduced in any form, by mimeograph or any other means,without permission in writing from the publisher.ISBN-978-81-203-4520-1The export rights of this book are vested solely with the publisher.Eighteenth Printing (Fifth Edition)ººJanuary 2012Published by Asoke K. Ghosh, PHI Learning Private Limited, M-97, Connaught Circus,New Delhi-110001 and Printed by Rajkamal Electric Press, Plot No. 2, Phase IV,HSIDC, Kundli-131028, Sonepat, Haryana.

ContentsForewordixPrefacexi1. Scope of Statistical Methods in Medicine1.1 Introduction 11.2 Estimation 21.3 Tests of Hypothesis1.4 Study Design 5Questions 61– 632. Role of Statistics in Clinical Medicine2.1 Introduction 72.2 Some Examples of Earlier Uses of Statistics2.3 Areas of Application of Statistics 8Questions 103. Role of Statistics in Preventive Medicine7– 10711 –133.1 Introduction 113.2 Some Early Examples 113.3 Areas of Application 11Questions 134. Variables14 –194.1 Introduction 144.2 Definition of Variables 144.3 Qualitative Variables 144.4 Quantitative Variables 154.5 Subjective and Objective Variables 164.6 Dependent and Independent Variables 174.7 Measurement of Variables 174.8 Scale of Measurement 184.9 Recording the Variables 184.10 Role of Computers 184.11 Quality of Data 18Questions 195. Frequency Distribution5.1 Introduction 205.2 Frequency Distributions20 –2520iii

ivCONTENTS5.3 Diagrams 215.4 Characteristics of a Frequency Distribution 25Questions 256. Measures of Central Tendency and Location26– 346.1 Introduction 266.2 Arithmetic Mean 266.3 Median 286.4 Mode 296.5 Position of Averages 296.6 Selection of the Appropriate Measure of Central Tendency 306.7 Geometric Mean 316.8 Harmonic Mean 326.9 Percentile 336.10 Use of Computer 34Questions 347. Measures of Dispersion35–437.1 Introduction 357.2 Range 357.3 Interquartile Range 367.4 Mean Deviation 377.5 Variance and Standard Deviation 387.6 Alternative Method of Calculating Standard Deviation 407.7 Coefficient of Variation 427.8 The Use of Computer 43Questions 438. n 44The Probability Scale 44Measurement of Probability 45Laws of Probability for Independent Events 46Conditional Probability 46Bayes’ Theorem 47Application of Bayes’ Theorem in Determining DiagnosticEfficacy 498.8 Other Applications of Probability 51Questions 549. Probability Distributions9.1 Introduction 559.2 Binomial Distribution 559.3 Poisson Distribution 579.4 Normal Distribution 589.5 ‘t’ Distribution 609.6 Other Distributions 61Questions 6155–61

CONTENTS10. Samplingv62–7010.1 Introduction 6210.2 Definitions 6210.3 Types of Population 6210.4 Sample 6310.5 Sampling Variation and Bias 6410.6 Nonprobability Sampling Techniques 6510.7 Probability (Random) Sampling Techniques 6510.8 Listing of Population 6910.9 Sample Size 69Questions 7011. Basis of Statistical Inference71–7511.1 Introduction 7111.2 Sampling Distribution 7111.3 Statistical Inference 7211.4 Type I and Type II Errors 74Questions 7512. Tests of Significance and Estimation76–8912.1 Introduction 7612.2 Procedure 7612.3 For Large Samples: Examples 7712.4 For Small Samples: Examples 8112.5 Estimation: Examples for Large Samples 8612.6 Estimation: Examples for Small Samples 8812.7 Reading Computer Output 88Questions 8913. Linear Regression and Correlation90–9913.1 Introduction 9013.2 Scatter Diagram 9013.3 Correlation and Regression 9113.4 Correlation Coefficient 9213.5 Regression Equation 9513.6 Restrictions 9613.7 Nonlinear Regression 9713.8 Multiple Regression 9713.9 Other Extensions 99Questions 9914. The Chi-Square Test14.114.214.314.4Introduction 100The Formula for Chi-Square 100Distribution of Chi-Square (χ2) and Degrees of FreedomSome Applications of Chi-Square Test 101100–107101

viCONTENTS14.5 Yates Correction 10514.6 Extension of 2 2 Table 10514.7 Precautions in Using the Chi-Square TestQuestions 10710615. Analysis of Variance15.1 Introduction 10815.2 The F-Test 10815.3 An Illustration of One-Way ANOVA15.4 Two-way ANOVA 11115.5 Assumptions of ANOVA 113Questions 113108–11310916. Non-parametric or Distribution-free Statistical Tests114–12116.1 Introduction 11416.2 Advantages of Non-parametric Tests 11416.3 Disadvantages of Non-parametric Tests 11516.4 Some Non-parametric Tests 11516.5 Some Illustrations 116Questions 12117. Vital Statistics122–13917.1 Introduction 12217.2 Uses of Vital Statistics 12217.3 Mechanism for Collection of Vital Statistics 12317.4 Basic Formulae for Calculation of Vital Statistics 12717.5 Mortality Rates 12917.6 Fertility Rates 135Questions 13918. Health Statistics140–15218.1 Introduction 14018.2 Utilisation of the Basic Data 14018.3 Sources of Health Statistics 14118.4 Problems in the Collection of Sickness Data 14218.5 Measurement of Sickness 14418.6 Hospital Statistics 14618.7 International Classification of Diseases 147Questions 15219. Standardised Death Rates and Life Tables19.1 Introduction 15319.2 Adjusted or Standardised Rates 15319.3 Life Tables 15919.4 Cox Proportional Hazards Model (Cox Regression)Questions 165153–165165

CONTENTS20. Demographyvii166 –17520.1 Introduction 16620.2 Population and Growth 16620.3 Age and Sex Composition 16720.4 Dependency Ratio 16920.5 Other Indices 16920.6 Fertility and Mortality 16920.7 Demographic Transition 17120.8 Population Estimation 172Questions 17521. Introduction to Research Methods176–18821.1 Introduction 17621.2 Research Question 17621.3 Literature Review 17721.4 Theoretical Framework or Model 17721.5 Research Protocol 17721.6 Formulation of Objectives and Research Hypothesis21.7 Population under Study 17921.8 Statistical Design 18021.9 Sample Size 18221.10 Methods of Data Collection 18321.11 Methods of Dealing with Non-response 18521.12 Data Processing 18721.13 The Constraints 187Questions 18822. Interventional Studies179189–20022.1 Introduction 18922.2 General Principles of Experimental Designs 18922.3 Common Designs 19222.4 Determination of Sample Size 19522.5 Clinical Trials 19522.6 Therapeutic Trials 19622.7 Prophylactic Trials 19822.8 Ethical Considerations 19922.9 Community Trials 19922.10 Repeated Measurement Studies 200Questions 20023. Sample Size Determination23.1 Introduction 20123.2 Specifications Needed to Calculate Sample Size23.3 Examples of Sample Size Estimation 20123.4 Useful Hints 207Questions 207201–207201

viiiCONTENTS24. Observational oduction 208Cross-sectional Studies 209Prospective Studies 209Retrospective Studies 210Sources of Bias in Observational Studies 212Controlling for Bias 213Causality 213Relative Advantages and Disadvantages of the Prospectiveand Retrospective Methods 21424.9 Confidence Intervals (CI) of Odds Ratio (OR) 21524.10 Measures of Potential Impact 21524.11 Some Comments 218Questions 21825. Data Processing25.1 Introduction 21925.2 Computer Hardware 21925.3 Computer Software 22025.4 Choosing a Computer System 22225.5 Role of Computer in Data Management25.6 Further Uses of Computers 22225.7 A Note of Caution 22325.8 Clues for using SPSS and Excel 224Questions 224219–22422226. Presentation of Data225–24026.1 Introduction 22526.2 Basic Principles 22526.3 Elements of a Table 22626.4 Classifications 22626.5 Presentation by Graphs and Diagrams 22926.6 Time Comparison 23026.7 Space and Attribute Comparisons 23226.8 Analysis of Time Series 23426.9 Special Diagrams for Clinical Research 237Questions 240Appendices241–253Bibliography255–262Answers to Selected Questions263–264Index265–268

ForewordIt is indeed my pleasure and privilege to write the Foreword for Introduction toBiostatistics and Research Methods.Dr. P.S.S. Sundar Rao joined Christian Medical College (CMC), Vellore, when theMadras University introduced the study of Biostatistics as a part of the syllabus ofPreventive and Social Medicine in 1957 for the M.B.B.S. students in all medicalcolleges of the University. During that time I was the Medical Superintendent of theCMC Hospital, and later from 1961 to 1970, I served as the Principal of the College andHead of the Department of Neurological Sciences. I had the privilege to work closelywith Dr. Sundar Rao in my research studies, and in the Research Committee. He madea significant contribution to the development and understanding of Biostatistics. Heand Dr. J. Richard had rendered considerable help and guided in severalepidemiological studies and in the research activities in CMC departments. They hadnot only helped CMC, but on a national level, had been conducting SummerCourses—advanced studies for teachers and research workers. They had also starteda regular M.Sc. (Biostatistics) course for the Madras University in their department.This book contains all the essentials of Biostatistics, research methods,demography and health statistics that lay a good foundation for anyone interestedin these subjects. All the examples are from the health field and are based on realexperience. I am pleased to recommend this book for the medical and health personneland for all those interested in Biostatistics.Padma Bhushan Dr. Jacob ChandyM.Sc. FRCS (C), FICS, FAMS, FIASCFormerly, Professor and Head,Department of Neurological Sciences, andPrincipal, Christian Medical College, Velloreix

Introduction To Biostatistics AndResearch MethodsPublisher : PHI LearningISBN : 978812034 5201Author : P S S Sundar RaoAnd J RichardType the URL : http://www.kopykitab.com/product/64 4 6Get this eBook

Biostatistics and Research Methods. Dr. P.S.S. Sundar Rao joined Christian Medical College (CMC), Vellore, when the Madras University introduced the study of Biostatistics as a part of the syllabus of Preventive and Social Medicine in 1957 for the M.B