SAMPLE SIZE DETERMINATION Sample size determination is the essential step of research methodology. It is an act of choosing the number of observers or replicates to include in a statistical sample. Sample size determination is the act of choosing the number of observations or replicates to include in a statistical sample. The sample size is an important feature of any empirical study in which the goal is to make inferences about a population from a sample. Precision A measure of how close an estimate is to the true value of a population parameter. Or it can be thought of as the amount of fluctuation from the population parameter that we can expect by chance alone in sample estimates. Degree of Precision This is presented in the form of a confidence interval (Range of values within which confidence lies). RESEARCH REPORT A research report is considered a major component of any research study as the research remains incomplete till the report has been presented or written. No matter how good a research study, and how meticulously the research study has been conducted, the findings of the research are of little value unless they are effectively documented and communicated to others. TYPES OF RESEARCH REPORT The research report is classified based on 2 things; Nature of research and Target audience. COHORT STUDIES A research study that compares a particular outcome in groups of individuals who are alike in many ways but differ by a certain characteristic is called as Cohort study. Cohort studies are a type of research design that follow groups of people over time. Researchers use data from cohort studies to understand human health and the environmental and social factors that influence it. CLINICAL TRIALS A clinical trial, also known as a clinical research study, is a protocol to evaluate the effects and efficacy of experimental medical treatments or behavioral interventions on health outcomes. This type of study gathers data from volunteer human subjects and is typically funded by a medical institution, university or nonprofit group, or by pharmaceutical companies and government agencies. Clinical trial vs. clinical study A clinical study is research conducted with the intent of gaining medical knowledge. Observational and interventional are the two main types of clinical studies. A clinical trial is an interventional study.

1. BIOSTATISTICS AND RESEARCH METHODOLOGY
Unit-3: designing the methodology
PRESENTED BY
Himanshu Rasyara
B. Pharmacy IV Year
UNDER THE GUIDANCE OF
Gangu Sreelatha M.Pharm., (Ph.D)
Assistant Professor
CMR College of Pharmacy, Hyderabad.
email: sreelatha1801@gmail.com

2. SAMPLE SIZE DETERMINATION
• Sample size determination is the essential step of research methodology. It is an act of choosing the
number of observers or replicates to include in a statistical sample.
• Sample size determination is the act of choosing the number of observations or replicates to include in
a statistical sample. The sample size is an important feature of any empirical study in which the goal is
to make inferences about a population from a sample.
• Sample size determination is the act of choosing the number of observations or replicates to include in a
statistical sample.
Or
• Sample size determination is the mathematical estimation of the number of subjects/units to be included
in the study.
 Need of sample size determination
Optimum sample size determination is required for the following reasons:
1. To allow for appropriate analysis.
2. To provide the desired level of accuracy
3. To allow validity of significance test.
 Sample size in quantitative studies
1. The larger the sample, the more representative
2. The larger the sample, the smaller the sampling error.
3. Descriptive studies and correlational studies require large samples.

3. 4. Quasi–experimental and experimental studies use smaller samples than descriptive and co -relational
studies.
Sample size in quantitative studies (Non-Experimental/ Descriptive Studies)
• Probability of value of parameters will fall within specified range, closely connected with the level of
significance for statistical tests.
• For example, we can be ‘95% confident’ that the true mean value lies somewhere within a valid 95%
confidence level, corresponds to significance testing at the 5% level (P < 0.05) of significance.
• Likewise, we can be ‘99% confident’ that the true mean value lies somewhere within a valid 99%
confidence level, corresponds to significance testing at the 1% level (P < 0.01) of significance.
 Precision
• A measure of how close an estimate is to the true value of a population parameter. Or it can be thought
of as the amount of fluctuation from the population parameter that we can expect by chance alone in
sample estimates.
 Degree of Precision
• This is presented in the form of a confidence interval (Range of values within which confidence lies).
For example, a survey of a sample of patients indicates that 35 per cent smoke.
• Two way of calculation in non-experimental studies
• Estimate mean value
• Estimate proportion%.

4. • Example 1: How large must a sample be to estimate the mean value of the population?
Suppose we wish to measure the number of times that the average patient with asthma consults her/his
general practitioner for treatment?
The formula to calculate the sample size for a mean estimate is: N =(SD/SE) 2
Where N = the required sample size, SD = the standard deviation, and SE = the standard error of the mean
The standard deviation could be estimated either by looking at some previous study or by carrying out a
pilot study.
Suppose that previous data showed that the standard deviation of the number of visits made in a year was
20.
First, the SE (standard error) is calculated by deciding upon the accuracy level which you require.
If you want a 95% confidence level, then divide the maximum acceptable MRE (Margin for Random
Error) by 1.96 to calculate the SE.
If instead you want a 99% confidence level, then divide the maximum acceptable MRE by 2.56 to
calculate the SE.
The standard error is 5 divided by 1.96 = 2.55
The formula as follows: N=(SD/SE) 2
(20/2.55)2 = (7.84)2
61.4 =61 (rounded to nearest patient)

5. • Example 2: How large must a sample be to estimate a proportion / percentage?
You want to conduct a survey of the proportion of men over 65 who have cardiac symptoms
Your significance level is 95%
Your acceptable margin for random error is plus or minus 2 per cent
From previous studies work you estimate that the proportion is about 20 per cent
a) Calculate the SE = ...MRE/1.96...............
b) Using the formula for the sample sizes for a proportion, calculate:
N=P(100%-P)/(SE)2
First, the SE can be calculated by dividing the confidence interval by 1.96 SE=2/1.96=1.02
We then calculate:
N=P(100%-P)/(SE)2
With P = 20% and SE = 1.02,
We have N=20(100-20)/(1.02)2
20×80/1.04
=1539

6. RESEARCH REPORT
• A research report is considered a major component of any research study as the research remains
incomplete till the report has been presented or written. No matter how good a research study, and how
meticulously the research study has been conducted, the findings of the research are of little value unless
they are effectively documented and communicated to others.
• Writing a report is the last step in a research study and requires a set of skills somewhat different from
those called for in actually conducting a research.
• A research report is a well-crafted document that outlines the processes, data, and findings of a
systematic investigation. It is an important document that serves as a first-hand account of the research
process, and it is typically considered an objective and accurate source of information.
• It is an important document that serves as a first-hand account of the research process, and it is typically
considered as an objective and accurate source of information.
TYPES OF RESEARCH REPORT
• The research report is classified based on 2 things; Nature of research and Target audience.
 Nature of Research
Qualitative Research Report
• This is the type of report is written for qualitative research. It outlines the methods, processes, and
findings of a qualitative method of systematic investigation. In educational research, a qualitative research
report provides an opportunity for one to apply his or her knowledge and develop skills in planning and
executing qualitative research projects.

7. Quantitative Research Report
• A quantitative research report is a type of research report that is written for quantitative research. Quantitative
research is a type of systematic investigation that pays attention to numerical or statistical values in a bid to find
answers to research questions.
 Target Audience
• Also, a research report can be said to be technical or popular based on the target audience. If you're dealing
with a general audience, you would need to present a popular research report, and if you're dealing with a
specialized audience, you would submit a technical report.
Technical Research Report
• A technical research report is a detailed document that you present after carrying out industry-based research.
This report is highly specialized because it provides information for a technical audience; that is, individuals
with above-average knowledge in the field of study.
• In a technical research report, the researcher is expected to provide specific information about the research
process, including statistical analyses and sampling methods. Also, the use of language is highly specialized and
filled with jargon.
• Examples of technical research reports include legal and medical research reports.
Popular Research Report
• A popular research report is one for a general audience; that is, for individuals who do not necessarily have
any knowledge in the field of study. A popular research report aims to make information accessible to
everyone.
• It is written in very simple language, which makes it easy to understand the findings and recommendations.
Examples of popular research reports are the information contained in newspapers and magazines.

8. Importance of a Research Report
• Knowledge Transfer: As already stated above, one of the reasons for carrying out research is to
contribute to the existing body of knowledge, and this is made possible with a research report. A research
report serves as a means to effectively communicate the findings of a systematic investigation to all and
sundry.
• Identification of Knowledge Gaps: With a research report, you'd be able to identify knowledge gaps for
further inquiry. A research report shows what has been done while hinting at other areas needing
systematic investigation.
• In market research, a research report would help you understand the market needs and peculiarities at a
glance.
• A research report allows you to present information in a precise and concise manner.
• It is time-efficient and practical because, in a research report, you do not have to spend time detailing the
findings of your research work in person. You can easily send out the report via email and have
stakeholders look at it.

9. Major Parts Sections
Preliminary Part 1. Title
2. Certificate/Authorization document
3. Contents
4. Preface & Acknowledgements
5. List of Tables/Figure
6. Acronyms (If applicable)
Main Body 1. Introduction
2. Review of Literature
3. Research Objectives/Questions/Hypotheses
4. Research Methodology
5. Data Analysis/Results/Discussion
6. Conclusions and Findings
7. Recommendations
End part 1. Endnotes/References
2. Appendices
3. Bibliography
4. Index
Different parts of Research Report

10. COHORT STUDIES
• A research study that compares a particular outcome in groups of individuals who are alike in many
ways but differ by a certain characteristic is called as Cohort study.
• Cohort studies are a type of research design that follow groups of people over time. Researchers use data
from cohort studies to understand human health and the environmental and social factors that influence it.
• The word “cohort” means a group of people.
• Cohort studies are a powerful tool for conducting research in human populations. They are a type
of longitudinal study design. Longitudinal studies follow participants over a period of time. People in
cohort studies typically share some characteristics, such as their location or their age.
• Cohort studies represent one of the fundamental designs of epidemiology which are used in research in
the fields of medicine, pharmacy, nursing, psychology, social science, and in any field reliant on 'difficult
to reach' answers that are based on evidence (statistics).
Types of cohort studies
• There are several types of cohort studies.
• Prospective cohort studies involve recruiting a group of participants and following them over time to
gather new data. Retrospective studies involve using preexisting data.
• For a prospective cohort study, researchers identify a topic they want to study. They then design the
study and recruit the participants that will best help them study the topic.
• For example, if they wanted to study rates of heart disease in older age, they would choose an age group
of younger adults with similar characteristics who do not have heart disease to use as their baseline.

11. For a retrospective cohort study, researchers analyze a group of people who already have certain
characteristics. They then look at existing data to jump back in time. For example, they might look at a
group of older adults with heart disease. Then they would analyze data about the group members’
medical history to see what factors could have contributed.
Examples of cohort studies
• In the past, there have been some very large and long-running cohort studies that have provided a lot of
data, serving researchers in different fields. These include:
Nurses’ Health Study
• One famous example of a cohort study is the Nurses’ Health Study. This was a large, long-running
analysis of female health that began in 1976. It investigated the potential long-term consequences of the
use of oral contraceptives.
• Researchers recruited the study’s second-generation cohort for the Nurses’ Health Study II in 1989. In
2010, researchers recruited the study’s third-generation cohort of nurses from across the United States and
Canada.
• The participants in the first cohort were married female nurses aged 30–55 years. The second and third
cohorts aimed to look at more diverse cohorts.
• The Nurses’ Health Study has provided many important insights. The following headlines are from news
stories published by MNT. They report on some of the findings from this huge study:
• Nuts may protect against heart disease
• Weight gain in early adulthood linked to health risks later in life
• Colon cancer: Could proinflammatory diets raise risk?

12. • Because the Nurses’ Health Study asked participants about their lifestyle choices, it yielded a lot of
information about the harms and benefits of various factors, including specific types of food in the diet.
Framingham Heart Study
• Another example of a long-running cohort study is the Framingham Heart Study. This study recruited
over 5,209 male and female participants in 1948 from around the area of Framingham, MA. Since then, the
study has served as a source of data for cardiovascular risk factors.
• A second cohort began in 1971 and a third in 2002. The study has made important contributions to the
understanding of heart health. The researchers are now looking into how genetic factors may affect
cardiovascular health risks.
Advantages
• The only observational study design that directly investigates risk of disease and the factors contributing
to it.
• Ethically safe.
• Multiple outcomes can be measured.
• They are good for rare types of exposures, e.g. an exposure to a chemical spill in a factory.
Disadvantages
• Not appropriate for rare diseases or those that take a long time to develop e.g. mesothelioma.
• Not appropriate for studying multiple exposures.
• Can be costly and time consuming.

13. Conduction of Cohort Studies

14. • The study we conduct to perform statistical analysis of our data can majorly be of two types —
Observational and Experimental.
 Observational Study
• In this type of study, we measure or survey members of a sample without trying to affect the members or
manipulating the variables. Here, we simply observe what is happening and record the observations.
• This type of study shows that there may be a relationship between variables but it is not necessary to be
a cause and effect (causal) relationship. And, even if the observational study shows a cause-effect
relationship, the evidence provided by it is generally considered to be weak.
• Some of the key points about observational studies are as follows:
• Observational studies are less expensive than experimental studies.
• The time required for the completion of observational studies can be several years to decades.
• Cohort studies and case control studies are two types of observational studies.
Cohort study: For research purposes, a cohort is any group of people who are linked in some way. For
instance, a birth cohort includes all people born within a given time frame. Researchers compare what
happens to members of the cohort that have been exposed to a particular variable to what happens to the
other members who have not been exposed.
Case control study: Here researchers identify people with an existing health problem (“cases”) and a
similar group without the problem (“controls”) and then compare them with respect to an exposure or
exposures.

15.  Experimental Study
• In this type of study, we randomly assign a treatment to a group so that the researchers can draw the
cause and effect (causal) conclusion. This random assignment of treatments is what distinguishes both the
studies (observational and experimental).
• This type of study is also sometimes called a scientific study because of the treatment involved in it.
• Some of the key points about experimental studies are as follows:
• Experimental studies are closely monitored.
• Experimental studies are expensive.
• Experimental studies are typically smaller and shorter than observational studies.
• Experimental studies are usually randomized, meaning the subjects are grouped by chance.
Randomized controlled trial (RCT): Eligible people are randomly assigned to one of two or more
groups. One group receives the intervention (such as a new drug) while the control group receives
nothing or an inactive placebo. The researchers then study what happens to people in each group. Any
difference in outcomes can then be linked to the intervention.

16. • A clinical trial, also known as a clinical research study, is a protocol to evaluate the effects and efficacy
of experimental medical treatments or behavioral interventions on health outcomes. This type of study
gathers data from volunteer human subjects and is typically funded by a medical institution, university
or nonprofit group, or by pharmaceutical companies and government agencies.
• The purpose of a clinical trial is to determine if a new treatment or test or a potential drug or medical
device works and is safe. A clinical trial can determine which medical approach might work best to treat
life-threatening diseases, such as cancer, diabetes, coronary heart disease and HIV/AIDS, along with other
equally pernicious and debilitating conditions. Potential treatments include drugs, medical devices,
vaccines, blood products or gene therapy.
• Clinical trial statistical analysis is the collection and interpretation of data to uncover patterns and trends.
It is an element of data analytics. In the context of business intelligence (BI), the statistical
analysis includes collecting and analysis of data samples.
• Preclinical biostatistics for health professionals in a lab can provide foundation data about how a drug
may work and its satisfaction. It is not a substitute for analysis that shows how the drug will collaborate
with the human body.
• The word “clinical trials” or “clinical research” denotes a study that has been conducted in people.
• An effective clinical trial process lasts until the developer produces a marketing application with the U.S
Food and Drug Administration (FDA) or regulatory assistance in another country for the medication to be
permitted for doctors to recommend to people.
• Clinical biostatistics services can help identify the best way to deploy resources to treat populations. To
control the epidemic, the goal is not only finding the best way to treat an infected person but also to control
the spread in the population.
CLINICAL TRIALS

18. Phase 0
• This phase differs significantly from other phases of clinical trials as it is not a required part of testing
for a new drug. However, the purpose of this phase is to expedite the drug approval process.
• It is the primary clinical trial that has been done among people; the main objective is to learn and
understand how a drug is processed in the body and how it affects the human body. In this trial test, a very
small drug dose will be given to 10 to 15 people.
Phase I
• The objective of Phase I is to determine the best dose among new drug sample with the fewest side
effects. The sample will be tested in a group of 15 to 30 people. Doctors start by providing a very low dose
of the drug to a few people. The higher dose is given to people only after the side effects are known, or the
severity is known.
• Phase I clinical trials are generally done among healthy volunteers, i.e. healthy people. Usually, 20 to 80
healthy volunteers participate in Phase I
Phase II
• Phase II trials further assess the safety and check whether the drug works. The drug is usually tried
among patients with a particular type of cancer. Phase II trials are conducted among groups of people with
a particular disorder compared to Phase I trials.
• Ideally, the role of a statistician can be quite varied in Phase II clinical trial. Statisticians help translate
the findings from Phase I into a Phase II design that aims to determine the dose and exposure range in
which the drug is active.
• Placebos are not typically used in this phase, either. Again, if the results look promising, the trial will
continue to the next phase.

19. Phase III
• To do this, researchers often employ a double-blind study approach during which neither the doctors nor
the patients know which treatment protocol the patient is receiving, the new one or the standard one.
Human subjects are selected at random and assigned a protocol. The purpose of this kind of study is to
eliminate the power of suggestion in other words, to eliminate subjective bias from the test results.
• Placebos may be used in some phase III studies. If the experimental treatment is found to be effective
and can be used safely, it is evaluated and potentially approved for use by the general population.
• It helps in comparing a new drug to the standard-of-care drug. These trials calculate the side effects of
each drug and which drug works better. Phase III trials enroll more than 100 patients.
• In Phases III, there will always be more than two treatment groups. The control group gets stand-of-care
treatment. The other groups get the new treatment, but neither you nor your doctor can select your group.
You will also not aware of which group you belong to until the trial is over.
• Phase 3 studies typically involve 300 to 3,000 participants from a particular patient population for which
the medicine are ultimately intended to be used.
• When one or more Phase 3 trials got over, the researchers inspect the outcome and select whether the
drug has proven effectiveness and an adequate safety profile in treating a disease.

20. Phase IV
It helps to test new drugs, which the FDA permits. The drug is tested among several hundred or
thousands of patients. It helps in short-lived and long-lasting side effects and safety identification among
the research. Some rare cases, side effects may only be identified in large groups of people. Doctors can
also learn more about how well the drug works and if it’s helpful when used with other treatment.
Once a drug or treatment has been approved for use by the general population, researchers will continue
to gather data from the clinical trial participants.
On average, it can take about 10 years for a drug to go from preclinical development to approval in the
U.S. The drug development process, from inception to approval, can cost pharmaceutical companies and
research firms millions and in some cases billions of dollars.
Clinical trial vs. clinical study
A clinical study is research conducted with the intent of gaining medical knowledge. Observational and
interventional are the two main types of clinical studies. A clinical trial is an interventional study.
In an interventional study, participants are put into groups and receive one or more interventions or
treatments, a placebo -- or sugar pill, or no intervention. Participants receive specific treatment according
to the research plan or protocol the researchers created.