#1
Which of the following is a measure of central tendency?
Standard Deviation
Variance
Mean
Range
#2
Which type of sampling method involves selecting individuals based on their availability and willingness to participate?
Random Sampling
Stratified Sampling
Convenience Sampling
Systematic Sampling
#3
Which statistical test is used to determine if there is a significant association between two categorical variables?
Chi-square test
ANOVA
T-test
Pearson correlation coefficient
#4
In a correlation coefficient, what does a positive value indicate?
A strong negative relationship between variables.
A weak positive relationship between variables.
A strong positive relationship between variables.
No relationship between variables.
#5
What does p-value represent in statistical hypothesis testing?
Probability of Type I Error
Probability of Type II Error
Probability of observing the data given that the null hypothesis is true
Confidence Interval
#6
In a randomized controlled trial, what is the purpose of randomization?
To ensure all participants have the same characteristics
To reduce selection bias and confounding variables
To increase external validity
To make the study more convenient
#7
What is the purpose of blinding in a clinical trial?
To conceal the treatment assignment from participants and/or researchers.
To ensure that the study sample is representative of the target population.
To minimize confounding variables.
To control for selection bias.
#8
What is the primary objective of a case-control study?
To estimate the prevalence of a disease in a population.
To establish a cause-and-effect relationship between an exposure and an outcome.
To investigate the association between a disease and potential risk factors.
To assess the efficacy of a new treatment.
#9
What is the purpose of a pilot study in research?
To test the statistical significance of the main study results.
To gather preliminary data and assess the feasibility of the main study.
To recruit a larger sample size for the main study.
To apply the final intervention or treatment to participants.
#10
What is the purpose of stratified random sampling?
To ensure that each stratum is equally represented in the sample.
To randomly select individuals from each stratum to form a representative sample.
To control for confounding variables by dividing the population into strata.
To increase the efficiency of the sampling process.
#11
What is the difference between observational studies and experimental studies?
Observational studies involve manipulation of variables, while experimental studies do not.
Experimental studies involve randomization, while observational studies do not.
Observational studies observe and measure variables without intervention, while experimental studies involve intervention and control.
There is no difference between them.
#12
Which statistical test is appropriate for comparing means of two independent groups?
Paired t-test
ANOVA
Chi-square test
Independent samples t-test
#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.
To cross-validate results obtained from different study sites.
To ensure blinding of both participants and researchers.
To examine the long-term effects of a treatment over an extended period.
#14
When is the use of a non-parametric test more appropriate than a parametric test?
When the data are normally distributed.
When the data have extreme outliers.
When the sample size is large.
When the data have a linear relationship.
#15
In a survival analysis, what does the Kaplan-Meier estimator estimate?
Mean survival time
Median survival time
Cumulative survival probability
Standard deviation of survival times
#16
What is the primary purpose of a sensitivity analysis in statistical modeling?
To assess the impact of outliers on the results.
To evaluate the model's performance under different assumptions or parameter values.
To identify the mean and standard deviation of the dataset.
To calculate the p-value for model significance.