#1
Which statistical measure is used to describe the spread or dispersion of a set of data?
Variance
ExplanationVariance measures how far a set of numbers is spread out from their average value.
#2
What is the basic reproduction number (R0) in epidemiology?
The average number of secondary infections produced by a typical case of an infection
ExplanationR0 quantifies the contagiousness of an infectious disease.
#3
In epidemiology, what does 'sensitivity' of a diagnostic test refer to?
The ability of the test to correctly identify those with the disease
ExplanationSensitivity measures how well a test correctly identifies individuals with the disease.
#4
Which statistical test is commonly used to determine if there is a significant association between two categorical variables?
Chi-square test
ExplanationChi-square test assesses whether there is a significant association between categorical variables.
#5
What is the difference between prevalence and incidence in epidemiology?
Prevalence refers to the proportion of individuals with a disease in a population at a specific time, while incidence refers to the rate of new cases in a population over a defined period.
ExplanationPrevalence is the proportion of existing cases, while incidence is the rate of new cases.
#6
What is the purpose of a confidence interval in statistics?
To provide a range of values within which the true value of a parameter is likely to fall
ExplanationConfidence intervals estimate the range within which the true population parameter is likely to lie.
#7
What is the main purpose of stratified sampling in epidemiological studies?
To divide the population into subgroups based on certain characteristics and then randomly select samples from each subgroup
ExplanationStratified sampling ensures representation from different subgroups to improve the generalizability of results.
#8
What is the primary purpose of randomized controlled trials (RCTs) in epidemiology?
To establish causality between an exposure and an outcome
ExplanationRCTs provide strong evidence for causality by randomly assigning participants to treatment groups.
#9
What does the term 'odds ratio' represent in epidemiology?
The ratio of the odds of an event occurring in the exposed group to the odds of it occurring in the unexposed group
ExplanationOdds ratio quantifies the association between exposure and outcome in a case-control study.
#10
Which of the following study designs is best suited to establish a cause-and-effect relationship between an exposure and an outcome?
Cohort study
ExplanationCohort studies follow individuals over time, allowing for the determination of causal relationships.
#11
What is the definition of relative risk (RR) in epidemiology?
The ratio of the probability of an event occurring in the exposed group to the probability of it occurring in the unexposed group
ExplanationRelative risk measures the likelihood of an outcome in one group compared to another.
#12
What does the term 'confounding' refer to in epidemiological studies?
The effect of an extraneous factor that distorts the association between the exposure and the outcome
ExplanationConfounding occurs when an external factor influences the observed association between exposure and outcome.
#13
What is the primary advantage of using relative risk (RR) over odds ratio (OR) in epidemiological studies?
RR provides a better estimate of the true association between exposure and outcome.
ExplanationRelative risk directly measures the magnitude of association, unlike odds ratio.