Webinar on Sample Size Calculation in Biomedical Research
(held on 08.09.2021)

Department of Community Medicine, Narayana Medical College, Nellore, Andhra Pradesh, India has organized a webinar entitled “Sample Size Calculation in Biomedical Research”.

The purpose of the webinar was to familiarize the faculty, Post-Graduation students with the use of sample size calculation and give them the skills needed for effective calculation of sample size for their research studies.

This webinar covers the statistical methods used to calculate sample sizes in Biomedical Research.


About the participant’s profile:

A total of 355 participants has been registered in this webinar. Out of 355, 44.51% participants from the state of Andhra Pradesh, India and 55.49% of participants outside of the state of Andhra Pradesh, India and also one participant from abroad (Malaysia) were registered during the program schedule time. In the state of Andhra Pradesh, 31.01% from the Narayana Medical College & Hospital, Nellore, and 68.99% of participants from other Colleges/Universities were registered during the program schedule time.

Out of 355 participants, 54.92% have attended the webinar.


About the Presenter (Resource Person) profile:

Dr. G. Ravi Prabhu, MD, Professor and Head, Department of Community Medicine, SV Medical College, Tirupati, Andhra Pradesh. He did his MBBS from Rangaraya Medical College, Kakinada in 1991 and MD (Community Medicine) from Osmania Medical College, Hyderabad in 1996. He has more than 23 years of experience in Teaching and Research. He worked as Principal of ACSR Government Medical College, Nellore from April 2016 to June 2018 (more than 2 years). He published more than 25 articles in International and National Journals and delivered more than 20 Guest Lectures in Various Universities and Colleges. Conducted more than 10 National Projects on ICDS Centres functioning, Safe Injection Practices, Evaluation of Voluntary Organizations, Verbal Autopsy Projects etc. Participated as Chairperson in Several National and State Conferences of IAPSM and IPHA all over India.


Areas Covered in the Session: –

  • Basic concepts of population and sample.
  • How to collect a sample?
  • Concept of Normal Distribution.
  • Tests of Statistical Significance based on Normal Distribution
  • How to calculate sample sizes for single mean & two means?
  • How to calculate sample sizes for single proportion & two proportions?
  • Use of types of error (Type I and Type II).
  • What is alpha error and beta error.
  • Types of Research studies in Biomedical research
  • How to calculate sample sizes for different types of research studies in biomedical research, such as Case-Control studies (Binary & Continuous exposure), prospective cohort study, Screening Tests.
  • Use of confidence intervals to calculate a sample size


Speaker has answered the following Questions related to the feasibility of this topic were:

  • How large of a sample will I need to collect in order to see a significant effect?
  • How many subjects will I need if I test an effect that is a bit larger? a bit smaller?
  • Derivation of formula is hectic exercise is there any rule of thumb for sample size calculation in particular study designs as in RCT, analytical etc.
  • What is the maximum value of E which can be taken for calculating sample size for proportion as well as mean?
  • Is there any special formula for RCT?
  • What value of P has to be taken when we study multiple proportions in a given study?
  • If alpha 0.7. Is it considered sir?
  • What should be the sample size required for pilot study?
  • Design effect means sir?
  • Absolute Precision till what percentage we can take to calculate the sample size?



What attendees learned after this webinar:

  • The basic inputs behind sample size calculation.
  • How study design can impact sample size.
  • How to prepare for a discussion on sample size with a statistician.


Dr. G Ravi Prabhu Lecture_page-0001