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FCPS Part 1 Biostatistics MCQs
Biostatistics questions test study designs and bias, measures of central tendency and spread, sensitivity, specificity and predictive values, and the interpretation of results.
Below are 5 free single-best-answer questions drawn from the most frequently examined biostatistics concepts, each with the answer and a rationale for every option. The full bank has 15 biostatistics concepts, each asked several different ways.
Free biostatistics questions
Question 1
Cohort 2×2 table, exposed in the top row (a, b) and unexposed below: relative risk equals:
- A. ad/bc
- B. c/(c+d)
- C. a/(a+b)
- D. a/(a+b) − c/(c+d)
- E. [a/(a+b)] / [c/(c+d)]
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Answer: E. [a/(a+b)] / [c/(c+d)]
Relative risk compares the probability of disease in the exposed group, a/(a+b), with that in the unexposed group, c/(c+d). It needs incidence, so it is valid only in cohort studies and trials.
Why not the others: ad/bc: the odds ratio. a/(a+b) − c/(c+d): attributable risk (risk difference). a/(a+b): the risk in the exposed alone. c/(c+d): the risk in the unexposed alone.
High-yield: RR = risk exposed ÷ risk unexposed; RR 1 means no association; OR is for case-control.
Question 2
Best graph to display the association between age and systolic pressure in 100 adults:
- A. Histogram
- B. Bar chart
- C. Forest plot
- D. Pie chart
- E. Scatter plot
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Answer: E. Scatter plot
A scatter plot places one continuous variable on each axis with a point per subject, so the direction and strength of a linear association can be seen. It is the standard display for correlation.
Why not the others: Bar chart: compares categories. Histogram: spread of one variable. Pie chart: parts of a whole. Forest plot: pooled study estimates.
High-yield: Two continuous variables = scatter plot; one = histogram.
Question 3
A screening test must miss as few affected people as possible. Which property must be maximised?
- A. Variance
- B. Prevalence
- C. Precision
- D. Specificity
- E. Sensitivity
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Answer: E. Sensitivity
Sensitivity is true positives over all diseased people, so every false negative lowers it. It is a property of the test and does not change with prevalence.
Why not the others: Specificity: lowered by false positives. Precision: repeatability of a measurement. Variance: spread of values. Prevalence: proportion of the population with disease. Incidence: new cases per time.
High-yield: False negatives lower sensitivity; false positives lower specificity; high sensitivity rules out when negative.
Question 4
Study starting from disease status and looking back at exposure:
- A. Cohort study
- B. Case series
- C. Cross-sectional study
- D. Randomised controlled trial
- E. Case-control study
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Answer: E. Case-control study
Case-control studies select subjects by outcome and retrospectively compare previous exposure, which suits rare diseases.
Why not the others: Case series: no comparison group. Cross-sectional study: exposure and outcome measured together. Cohort study: starts with exposure. Randomised controlled trial: assigns intervention.
High-yield: Case-control = outcome first, odds ratio; cohort = exposure first, relative risk.
Question 5
Mean of these ten values: 38, 41, 39, 44, 40, 37, 43, 42, 41, 40
- A. 42.5
- B. 38.5
- C. 41.0
- D. 39.5
- E. 40.5
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Answer: E. 40.5
Mean is the sum divided by the number of values. Here 324 divided by 8, or 405 divided by 10 for the first set, gives 40.5.
Why not the others: Median of set two: equals 41.0, not the mean. Addition slip: gives 38.5 or 39.5. Division slip: gives 42.5.
High-yield: Mean = sum ÷ n; median = middle of ranked values; mode = most frequent.
Keep going with biostatistics
Anaesgen brings every concept back on a spaced-repetition schedule timed to your exam date, as a different question each time, with full mock papers for Paper 1 and 2.
Get full access Try the 5 sample questionsHigh-yield biostatistics one-liners
The most-tested biostatistics concepts, as a clue and the answer it points to:
- Cohort, risk exposed ÷ risk unexposed → [a/(a+b)] / [c/(c+d)].
- Two continuous variables, one dot per subject, correlation → scatter plot.
- False negatives rise, screening to miss no cases, TP/(TP+FN) → sensitivity.
- Disease versus no disease, retrospective exposure, odds ratio → case-control.
- Sum 405 ÷ 10, or sum 324 ÷ 8 → 40.5.
- Case-control, no denominator, ad/bc → odds ratio.
- Proportion of positives that are true, TP/(TP+FP), prevalence-dependent → PPV.
- Square root of variance, same units as data → standard deviation.
- Sum ÷ n, arithmetic average, dragged by outliers → mean.
- Divide into strata, then random sample within each → stratified random sampling.
- Even n, sort first, average 4th and 5th values → median.
- Categorical, presence/absence, two groups → chi-square.
- Vomiting yes/no, blood group, sex, unordered → nominal.
- Mild/moderate/severe, ASA grade, ranked unequal gaps → ordinal.
- Statistical analysis, p-value → result unlikely due to chance.
Other FCPS Part 1 subjects
AnatomyPharmacologyPathologyBiochemistry & GeneticsCardiovascularNeurophysiologyMicrobiologyHaematologyGeneral PhysiologyImmunologyEndocrineRespiratoryEmbryologyObstetrics & GynaeRenal & Acid-BaseHistologyGI & LiverPhysics
New to the exam? Read the FCPS Part 1 exam guide: dates, format and a 12-week study plan.