For Medical Students and Research Workers
Seventh Edition
BK Mahajan MBBS DPH FCGP FIAPSM
Professor of Preventive and Social Medicine At Jamnagar (1960–73) and Sevagram (1973–82) Deputy Director Health Services erstwhile Mumbai State (1958–60) and Sr. Consultant, Integrated Child Development Services Department of Gastroenterology and Human Nutrition Unit AIIMS, Ansari Nagar, New Delhi 110029 (1982–87) Consultant of Delhi Council of Child Welfare Statistical Check by Sh BD Malhotra and Prof KR Sundram Head of Department of Biostatistics, AIIMS,
New Delhi, India
Revised by Arun Bhadra Khanal
Lecturer of Statistics Nobel College, Kathmandu Pokhara University,
Nepal
Foreword by VP Reddaiah
Jitendar P Vij
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Methods in Biostatistics
© 2010, Jaypee Brothers Medical Publishers
All rights reserved. No part of this publication should be reproduced, stored in a retrieval system, or transmitted in any form or by any means: electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of the author and the publisher.
First Edition: 1967
Seventh Edition: 2010
9788184487138
Typeset at JPBMP typesetting unit
Printed at Ajanta
Lalit
(Born on Tuesday, September 12, 1944)
This work is dedicated to the loving memory of Author's only son, LALIT who lost his life on way to USA for higher studies in mechanical engineering, in the Air India Boeing accident near Mont Blanc on January 24, 1966, along with 116 others including the world-renowned Atomic Energy Scientist, Dr Homi Bhabha.6
7About the Author
After a brilliant academic career, Dr BK Mahajan got a wide and rich experience as a Senior Health Administrator for 12 years in old Bombay state and over 22 years as Professor of preventive and Social Medicine. He was Sr. Consultant, ICDS Aug. 1982 to Dec. 1987 and was also Consultant of DCCW.
In 1961–62, he was deputed to visit medical schools, in the UK and Europe to study teaching of Prevention and Social Medicine. He had read several papers at All India Conferences and published many of them in Journals of repute, apart from having written book on his subject. From 1973 to 1982 he had served as Professor of Preventive and Social Medicine at Sevagram (Wardha) where he was continued as life long Professor Emeritus. Since 1982 to 1988 he was selected as Sr. Consultant for ICDS at AIIMS, New Delhi to serve the entire country.
He was honoured to deliver Dhanwantri Oration at IAPSM Conference, Bangalore in 1976, Late Rama Murthi Guest Oration at Hyderabad in 1980 and Dr Rameshwar Sharma Oration at Bikaner in 1983. He was Secretary of IAPSM in 1979–80, first President of IAPSM in 1983 and was President of Ind. Assoc. of Comm. Diseases from 1980.
He was an Indian Delegate to Seminar on Medical Education in SEA Countries, at Pokhra (Nepal) in 1976.
He traveled widely in India, UK, Europe, USA and Japan to study the problems of Medical Education in general and of teaching Preventive and Social Medicine/Community Medicine and Biostatistics in particular.
The very next day after retiring from AIIMS, he was requested to join as Medical Consultant to Delhi Council of Child Welfare where he was in 1997 and DCCW wished him to continue as long as his health permited.
He had been active member of IMA too and was playing a very vital role in various activities of Delhi Medical Association.8
9Foreword
It is my proud privilege to write the foreword to Methods in Biostatistics by Dr BK Mahajan, who is the grand old man of Preventive and Social Medicine. Most of the Biostatistics books available to Indian students are by foreign nonmedical statisticians who use mathematical formulas which make medical people averse towards statistics. They fail to understand and appreciate the use of statistics in their continuing education by literature review, practice and research.
But this book has been written by an eminent medical person who understands the mentality of the medical people towards statistics. He has written this book from the perspective of medical people in simple language with very little mathematical formulas and Indian examples. This makes medical people accept and master statistics. The fact that this book has come to 7th edition in 43 years is an eloquent testimony to the popularity of the book.
This book is a great boon to medical students both undergraduates and postgraduates who want to be self-significant in statistical analysis. It is a book that every medical person and medical college library must possess. I wish him success in his endeavor and happy to release this edition.
Dr VP Reddaiah
Prof & Head Centre for Community Medicine, AIIMS
11Preface to the Seventh Edition
Scientific methods of statistical analysis, which were almost unknown a few years ago, today provide very effective data for understanding and in-depth study of any branch of knowledge. It facilitates interpretation of facts and application in medical sciences.
Fruits of any new technique of challenge and different modalities in treatment have to be compared. I am happy to bring the seventh edition in 2010 after the sixth in 1997. After each edition reprints had to be prepared by my publisher Jaypee Brothers in view of everincreasing damand in India and abroad because of its easy and simple understanding. There is no such averseness as existed in the past. All medical research workers too realize application of biostatistics as a science for proper evaluation of the work done—be it thesis or presentation of paper, read or published in journals of repute. There is continuous rising demand for a simple book like this, in which mathematical complexities are avoided and students can easily follow the biostatistics as a science of variation. Simple and familiar examples have been provided abundantly.
Use of computers for which special chapter has been added in brief has greatly facilitated the analysis of the work done in medical field and biosciences too.
Present edition is thoroughly revised and updated. In this context the chapter “Computer Application in Biostatistical Analysis: An SPSS Manual” has been added.
BK Mahajan
12Acknowledgments
I am grateful to Dr Prof Reddaiah for writing Foreword to this edition.
I am very grateful to the experts whose remarks are given at the end of the title of this book. I cannot help mentioning my gratefulness to late Shri BD Malhotra. Statistician, Prof KR Sundaram, Head of Biostatistical Department in AIIMS and Shri DA Shah, Statistician in Medical College, Surat.
I highly appreciate the all long cooperation and genuine support given by Shri Jitendar P Vij, Chairman and Managing Director of Jaypee Brothers Medical Publishers (P) Ltd. who are now the largest medical publishers in India. They render all help to experts in the field of medicine to publish their works. I would be failing in my duty if I don't express my gratitude to Mr PG Bandhu (Director). It is because of their cooperation that I could complete the present volume.
Dr KK Agarwal, Cardiologist at Mool Chand Hospital has given all help despite his busy schedule. A new chapter on computer is due to his help. Dr (Col) BR Chopra, Cardiology Department gave a lot of encouragement by his ever-smiling face.
Dr Bir Singh, Additional Professor of Community Medicine, AIIMS also joined me in updating demography and vital statistics and going through the initial draft but because of his other heavy involvements he did as much as he could.
I am grateful to Dr G Anjneyulu, Prof and Head of PSM, Hyderabad, Maj HS Ratti, MD (PSM), Dy Director (MHS), Dr Nitika Arora and Manu her brother, Shri Praful, Mrs Sapna Bhasin, Shri Jeya Shanker and Km Alpna. I am sincerely thankful to the dedicated team of Jaypee Brothers for their whole hearted cooperation. Dr Sultan Ahmed and Mrs Samina Khan definitely deserve a pat on their back.
Last but not the least I must sincerely thank Smt Anjna Devi Mahajan my wife and Mrs Nandini Churamani my grand daughter for sparing so much time in this dedicated work.