Research Methodology: Study Design, Sample Size Calculation and Power

This document presents a solution to a research methodology assignment, addressing key concepts such as study design, variable definition, sample size calculation, validity, reliability, and statistical power. It includes multiple-choice questions, open-ended questions related to research scenarios (e.g., the impact of Carica papaya on platelet levels in dengue fever patients), and discussions on the importance of reading research articles. The solution covers topics like quasi-experimental studies, cross-sectional studies, randomized block designs, purposive sampling, operational definitions of variables, and hypothesis testing. It further explains the steps involved in sample size calculation, the differences between validity and reliability, and the significance of alpha and beta errors in research. The document is available on Desklib, a platform providing study tools and resources for students.

Running head: RESEARCH METHODOLOGY 1
Research Methodology
[Name of Student}
[Institutional Affiliation]
[Date of Submission]

RESEARCH METHODOLOGY 2
SECTION (A): One Best answer
1. Quasi experimental study is suitable to?
(b). When randomization is impossible
2. Statistical Analysis in a cross sectional study
(c). has its own strength to be compared with other study design.
3. Randomized Block Design is utilized when the confounder is?
(c). adjusted based on randomization procedure
4. Purposive sampling is?
(c). recommended if researcher has logic issues.
5. Study population is?
(a) Is a population in which inference of the data will be concluded
6. Operational definition of variable is?
(a). an explanation on how the variable is measured.
7. Sample size calculation depends on?
(a) Study setting
8. In order to calculate sample size based on objective “to determine prevalence of any
disease”, the most appropriate reference prevalence value would be from the study which
was conducted
(b). among respondents with almost similar biological characteristics with the
current study

RESEARCH METHODOLOGY 3
9. Two-tailed hypothesis is appropriate for determining
(d). significance difference of hemoglobin between gender
10. Sample size calculation is not necessary in study which involve
(c). caretakers of the patients
11. Objectives of the study is determined by
(c). Research questions
12. One of characteristics of research objectives include:
(b) It is well understood
13. Preliminary information that need to be understood for sample size calculation include?
(c). i, ii, iii, v.
14. Which of the following actions will reduce the sample size
(a) By increasing the beta error to 25%
15. In constructing questionnaires, the following issues need to consider EXCEPT
(d) Confidence interval
SECTION (B): Answer ALL questions
Question 1.
a. State the most appropriate tittle for the study above
Title: “Does Carica papaya (papaya leaves) increase platelets level in patients with acute
dengue fever?”

RESEARCH METHODOLOGY 4
b. Name the most appropriate study design and state ONE (1) reason why design is chosen
Cross sectional study; this is because the observation defines population at a single point
in time interval
Question 2.
a. State ONE (1) of possible research question for the above scenario.
Research question: “Ways on how to reduce the morbidity due to dengue in village x”
b. Explain approach on how you are going to define the variables identified in this research
i. Variable one : Time in years
ii. Variable two: Number of patients
c. State ONE (1) reason why defining variables is important in research proposal
i. Defining variable in research is important in research proposal since they have effect
on the results and thus enables inferences about them.
Question 3.
a. State the objective and hypothesis of the above study (2 marks)
The objective of the study is “effectiveness of acupuncture to overcome adolescent
obesity as a factor contributing to early onset of diabetes mellitus of type 2.
b. State steps on how we going to calculate sample size (4 marks)
Step 1: Specifying a hypothesis of the test that I would be testing;
Step 2: Determination of the level of the significance and for this case, I would use alpha =
0.05

RESEARCH METHODOLOGY 5
Step 3: Estimation of other values of the parameters necessary to compute the power function
such as the standard error and standard deviation.
Step 4: Specification of the intended power of the test for this study and for this case, I would
prefer a power of 0.9.
Question 4.
Briefly explain the validity and reliability. Explain how we ensure the data for our study
is valid and reliable (5 marks).
Validity refers to the accuracy of the assessment while reliability refers to the extent to
which assessment are consistent.
To enhance the validity and reliability of data in the research, the following can be done
to improve on the reliability and validity of the data;
i. The approach of data collection from the sources or study should be transparent
and systematic in nature.
ii. Audit trial should be maintained by clearly documenting the flow and processing
of the data.
iii. Member checking the data to ensure that the approach is reliable; it means
drawing the data using the prescribed or any systematic way.
iv. Also, one can check to ensure that the data is reliable and valid by having some
kind of the focus group with samples of researches to ascertain whether your data
is what is supposed to be.
Question 5.

RESEARCH METHODOLOGY 6
Discuss about power of the study, confidence level, and alpha and beta error in sample
size calculation (5 marks).
The power of study refers to the number or the percentage that indicates a probability that
a study will obtain a statistical significant effect. For instance, a power of 0.9 means that
a study when conducted repeatedly over time, is likely to produce a statistical significant
results 9 times out of 10. Confidence level in sample size determination tells the surety of
how the size can be while the beta and alpha errors suggest the size of the sample size to
be used as the sample size increases beta while reduces alpha.
Question 6.
a.
Week Authors/
Article tittle
Research
question
Summary/
key-points
Comments about it
internal validity (study
design, sample size,
study analysis and
conclusion)
1 JA Cabrioles
and T Taylor.
“Psychology of
the Addictive
behaviours”
To assess
prescription
drug misuse
and illicit
drugs in
Hispanic
The illicit
substance use
has increased
in Hispanics.
Valid research based on
Sample size of 200
respondents. The use of
illicit substance has
Summarise one of the
articles from your
literature review in the

RESEARCH METHODOLOGY 7
following template.
[Only ONE selected
articles per week, not
necessarily related to
actual research work]
(15marks) increased in
Hispanics.
2 Occupational
health and
Work fatigue
“Identifying
Effective Risk
Management
for work-
related Fatigue
and Recovery
to reduce
fatigue related
errors among
Nurses”
There were
several factors
impacting on
the work
performance
of the
employees
including the
demographic
characteristics
of nurses such
as age and
gender.
Valid study on a
sample population of
about 250 nurses
(Respondents).
In this article, there are
other factors that cause
encouragement of the
disease such as social
belongings or
awareness of
precautions,
involvement in leisure
activities or workplace
activities.
3 T Bennett and
K Holloway.
To determine
the
There is
significance
Reliable and valid
study based on a

RESEARCH METHODOLOGY 8
“The
International
journal of
offender
therapy and
comparative
criminology
approximate
prevalence of
drug and
alcohol related
crime among
university
students in
seven
universities in
United
Kingdom to
assess whether
there is
difference
between
substance
users and
offenders
difference
between
substance
users who
offend and
those who do
not offend.
sample population of
1500 university student
across the seven
universities in United
Kingdom.
b. Give reasons why reading of articles is important in conducting any research
(5marks)

RESEARCH METHODOLOGY 9
i. The articles are highly credible and offer clarity; the information contained in the
articles are verified and thus reading them positively influences ones overall quality
work as well as enriching with facts and truth.
ii. The articles offer evidence for their claims and comes with research options which
helps in widening the researcher’s scope in the study.
iii. The articles are known to provide case studies which are excellent sources of in-depth
information and knowledge hence much useful the researcher.
iv. Reading article broadens the perspective of a research since they contain different
thoughts and opinions relating to the case study or topic.
v. Reading articles provide great wealth of knowledge to the researcher while
conducting any research.
References
Der, G. & Everett, B. S. (2011) A Handbook of Statistical. (2nd Ed). Boca
Raton, FL: Chapman and Hall/CRC.
Everett, B. S. (2008) Research Methods and Statistical Analysis. (1st Ed). Boca Raton, FL:
Chapman and Hall/CRC.

RESEARCH METHODOLOGY 10
Trevor, B. & Holloway, K. (2018). Drug and Alcohol-related crime among university students.
International Journal of offender therapy and comparative criminology. Boca Raton,
Chapman.
Jose, C. (2013) Prescription drug misuse, illicit drug use, and their potential risk and protective
correlates in a Hispanic college student sample. Experimental and clinical
psychopharmacology. Cambridge Press. Cambridge.