#1
Which of the following is a measure of central tendency?
Mean
ExplanationMean is a measure of central tendency representing the average value of a dataset.
#2
Which type of sampling method involves selecting individuals based on their availability and willingness to participate?
Convenience Sampling
ExplanationConvenience sampling involves selecting subjects based on their easy accessibility and willingness to participate.
#3
Which statistical test is used to determine if there is a significant association between two categorical variables?
Chi-square test
ExplanationThe Chi-square test assesses the association between two categorical variables in a contingency table.
#4
In a correlation coefficient, what does a positive value indicate?
A strong positive relationship between variables.
ExplanationA positive correlation coefficient suggests that as one variable increases, the other variable tends to increase as well.
#5
What does p-value represent in statistical hypothesis testing?
Probability of observing the data given that the null hypothesis is true
ExplanationP-value indicates the likelihood of obtaining the observed data if the null hypothesis were true.
#6
In a randomized controlled trial, what is the purpose of randomization?
To reduce selection bias and confounding variables
ExplanationRandomization ensures that treatment groups are comparable, reducing bias and confounding factors.
#7
What is the purpose of blinding in a clinical trial?
To conceal the treatment assignment from participants and/or researchers.
ExplanationBlinding prevents bias by keeping participants and/or researchers unaware of the treatment assignments.
#8
What is the primary objective of a case-control study?
To investigate the association between a disease and potential risk factors.
ExplanationCase-control studies analyze associations between diseases and potential risk factors through retrospective observation.
#9
What is the purpose of a pilot study in research?
To gather preliminary data and assess the feasibility of the main study.
ExplanationPilot studies collect initial data and evaluate the practicality and viability of conducting a larger study.
#10
What is the purpose of stratified random sampling?
To control for confounding variables by dividing the population into strata.
ExplanationStratified random sampling ensures representation of subgroups within a population, helping control for confounding variables.
#11
What is the difference between observational studies and experimental studies?
Observational studies observe and measure variables without intervention, while experimental studies involve intervention and control.
ExplanationObservational studies passively observe variables, while experimental studies actively intervene and control variables.
#12
Which statistical test is appropriate for comparing means of two independent groups?
Independent samples t-test
ExplanationThe independent samples t-test compares means of two groups drawn from independent populations.
#13
What is the purpose of a crossover study design in clinical research?
To compare the effects of different treatments within the same subject over two or more periods.
ExplanationCrossover studies assess the effects of multiple treatments within the same subjects over distinct time periods.
#14
When is the use of a non-parametric test more appropriate than a parametric test?
When the data have extreme outliers.
ExplanationNon-parametric tests are suitable for data with extreme values, as they do not rely on assumptions about the data distribution.
#15
In a survival analysis, what does the Kaplan-Meier estimator estimate?
Cumulative survival probability
ExplanationThe Kaplan-Meier estimator calculates the probability of surviving up to a given time point in survival analysis.
#16
What is the primary purpose of a sensitivity analysis in statistical modeling?
To evaluate the model's performance under different assumptions or parameter values.
ExplanationSensitivity analysis examines how changes in model assumptions or parameters affect the results, assessing the model's robustness.