Questions & Answers
Browse all 16 questions from the
Statistical Facts in Human Physiology and Health study set below.
Each question shows the correct answer — select a study format above to practice interactively.
1
In a large-scale epidemiological study investigating the incidence of a specific type of cancer, what is the most appropriate statistical measure to describe the rate at which new cases occur in a defined population over a specific time period?
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A
Prevalence
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B
Sensitivity
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C
Incidence Rate
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D
Positive Predictive Value
2
When analyzing the results of a clinical trial for a new medication designed to lower blood pressure, a statistically significant p-value (e.g., p < 0.05) typically indicates:
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A
The treatment is definitely effective.
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B
There is strong evidence against the null hypothesis.
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C
The observed effect is solely due to chance.
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D
The sample size was too small.
3
A meta-analysis combining data from multiple randomized controlled trials on a new vaccine's efficacy found a pooled odds ratio of 0.30 (95% CI: 0.20-0.45). What does this statistically significant result suggest about the vaccine?
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A
The vaccine increases the risk of the disease.
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B
The vaccine is associated with a reduced risk of the disease.
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C
There is no discernible effect of the vaccine.
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D
The studies included were too heterogeneous to draw conclusions.
4
In medical diagnostics, the area under the Receiver Operating Characteristic (ROC) curve (AUC) is a measure of a diagnostic test's ability to discriminate between:
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A
Two groups of healthy individuals.
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B
Two groups of individuals with the same disease.
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C
Individuals with and without a specific condition.
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D
Different stages of the same disease.
5
Survival analysis, commonly used in oncology, estimates the probability of an event (like death) occurring over time. The Kaplan-Meier estimator is a non-parametric statistic used to estimate:
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A
The incidence of new cases.
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B
The prevalence of existing cases.
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C
The survival function.
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D
The hazard ratio.
6
When assessing the reliability of a diagnostic test, a high specificity indicates that the test is good at:
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A
Correctly identifying individuals with the disease.
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B
Correctly identifying individuals without the disease.
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C
Minimizing false positive results.
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D
Minimizing false negative results.
7
In a study examining the relationship between exercise frequency and cardiovascular health, a Pearson correlation coefficient of -0.75 was calculated. This indicates:
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A
A weak positive linear relationship.
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B
A strong negative linear relationship.
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C
No linear relationship.
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D
A weak negative linear relationship.
8
The standard deviation is a statistical measure that quantifies:
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A
The average of a dataset.
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B
The central tendency of a dataset.
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C
The spread or dispersion of data points around the mean.
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D
The difference between the maximum and minimum values.
9
In pharmacokinetics, the concept of bioavailability, often expressed as a percentage, refers to the fraction of an administered dose of an unchanged drug that reaches:
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A
The liver.
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B
The stomach.
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C
The systemic circulation.
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D
The site of action.
10
When comparing the average blood glucose levels of two groups of patients (diabetic vs. non-diabetic), an independent samples t-test is a common statistical tool used to determine:
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A
If the variances of the two groups are equal.
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B
If there is a statistically significant difference between the means of the two groups.
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C
The correlation between glucose levels and age.
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D
The proportion of patients in each group.
11
The Poisson distribution is a discrete probability distribution that is often used to model the number of events occurring within a fixed interval of time or space. In a health context, it could be used to model:
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A
The height of individuals in a population.
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B
The number of births in a hospital ward per day.
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C
The distribution of blood pressure values.
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D
The weight of newborns.
12
In genetic epidemiology, linkage disequilibrium (LD) refers to the non-random association of alleles at different loci. High LD in a population suggests:
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A
Alleles are inherited independently.
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B
Alleles are often inherited together due to proximity on a chromosome or selective forces.
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C
There are no genetic mutations.
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D
The population is in Hardy-Weinberg equilibrium.
13
When a confidence interval for the mean difference between two groups does not include zero, it generally implies:
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A
There is no statistically significant difference between the group means.
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B
There is a statistically significant difference between the group means.
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C
The sample size was insufficient.
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D
The data are not normally distributed.
14
The concept of 'effect size' in statistical analysis is important because it quantifies:
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A
The probability of rejecting a false null hypothesis.
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B
The magnitude of the difference or relationship observed, independent of sample size.
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C
The variability of the data within a group.
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D
The proportion of variance explained by a statistical model.
15
In studies of chronic diseases, the 'hazard function' (or hazard rate) in survival analysis represents:
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A
The probability of surviving up to a certain time point.
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B
The cumulative probability of an event occurring by a specific time.
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C
The instantaneous rate of an event occurring at a specific time, given survival up to that time.
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D
The proportion of the population that has experienced the event.
16
When a statistical model is used to predict the risk of developing a disease based on multiple predictor variables (e.g., age, BMI, smoking status), the coefficients (often denoted as beta coefficients) in logistic regression represent:
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A
The absolute change in risk for a one-unit increase in the predictor.
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B
The change in the log-odds of the outcome for a one-unit increase in the predictor.
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C
The probability of the outcome occurring.
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D
The correlation between the predictor and the outcome.
