Biostatistics & Study Design USMLE Step 1 Practice Questions
64 board-style USMLE Step 1 questions in Biostatistics & Behavioral Science. Each question shows the correct answer; create a free account for the full explanation and adaptive practice.
- USMLE Step 1 · medium1. During rounds with medical students, an attending physician examines a 33-year-old man in the intensive care unit who suffered second-degree burns over 24% of his body-surface a…
- USMLE Step 1 · easy2. Based on these results, what is the sensitivity of the interferon-gamma-based assay for the diagnosis of tuberculosis in this study?
- USMLE Step 1 · medium3. A 45-year-old man with no significant past medical history undergoes genetic screening as part of a research study investigating protective factors against hereditary hemochroma…
- USMLE Step 1 · medium4. A researcher designs two prospective studies to investigate whether dietary sodium restriction reduces the incidence of atrial fibrillation in older adults. Study A enrolls 200…
- USMLE Step 1 · hard5. A researcher compares crude mortality rates between a retirement community (mean age 72, BP 138/82, HR 68) and a nearby university town (mean age 24, BP 118/76, HR 62). The reti…
- USMLE Step 1 · medium6. Investigators are designing an observational study comparing fracture risk in chronic glucocorticoid users and nonusers. They are particularly concerned that age and sex differ…
- USMLE Step 1 · hard7. A 35-year-old woman on oral contraceptives presents with left leg swelling, pain, and warmth. Vital signs show BP 118/76, HR 92, RR 16, temp 37°C, SpO2 98%. Doppler ultrasound c…
- USMLE Step 1 · medium8. A epidemiologic study examining 5,000 patients finds coffee consumption associated with higher lung cancer incidence (RR 2.1). However, after stratifying data by smoking status,…
- USMLE Step 1 · medium9. A prospective cohort study follows 200 night-shift workers and 400 day-shift workers for 5 years to assess new onset hypertension. By the end of follow up, 40 night-shift worker…
- USMLE Step 1 · medium10. Investigators study a possible association between a pesticide and Parkinson disease. They enroll 120 patients with Parkinson disease and 200 controls without Parkinson disease.…
- USMLE Step 1 · medium11. A cancer screening program detects numerous tumors with excellent 10-year survival rates. However, interval cancers discovered between screening visits in asymptomatic patients…
- USMLE Step 1 · medium12. A hospital initiates annual low-dose CT screening for high-risk smokers (age 55-75, ≥30 pack-years). Five years later, screened patients (BP 138/82, HR 78, RR 16, SpO2 98%) demo…
- USMLE Step 1 · medium13. A 34-year-old woman with fever (38.9°C), cough, and myalgias presents to the emergency department in July. Rapid influenza assay is positive. Chest X-ray shows no infiltrates. S…
- USMLE Step 1 · medium14. A rapid screening test for celiac disease has the same sensitivity and specificity in all populations. A family medicine clinic uses the test in asymptomatic adults, whereas a g…
- USMLE Step 1 · easy15. A 58-year-old man with no prior colorectal cancer screening presents for evaluation. A new blood test measuring carcinoembryonic antigen (CEA) currently uses a threshold of 10 u…
- USMLE Step 1 · easy16. A new antiviral medication is introduced for a chronic infection in a city of 1 million people. The drug does not prevent new infections, but it markedly shortens the duration o…
- USMLE Step 1 · easy17. A county health department follows 20,000 residents for 1 year after a contaminated water exposure. At baseline, 200 residents already have documented immunity to hepatitis A fr…
- USMLE Step 1 · easy18. A 72-year-old man with newly diagnosed pancreatic cancer presents with jaundice, weight loss of 8 kg over 2 months, and epigastric pain. Vital signs: BP 118/76, HR 92, RR 18, Te…
- USMLE Step 1 · medium19. A 30 year old primigravid woman experiences an intrauterine fetal demise at 32 weeks' gestation. In the same hospital that year, there are 8 late fetal deaths and 12 neonatal de…
- USMLE Step 1 · medium20. A nested case control study of venous thromboembolism is conducted within a large cohort of women using oral contraceptives. Each time a new thrombosis case occurs, controls are…
- USMLE Step 1 · medium21. A longitudinal diabetes study has intermittent missing hemoglobin A1c values because some patients miss clinic appointments but later return. Investigators use patients' prior A…
- USMLE Step 1 · medium22. A multicenter hypertension trial finds that a small number of blood pressure readings are missing because some laboratory printouts were accidentally destroyed in a flood affect…
- USMLE Step 1 · hard23. A prospective cohort study follows 200 adults with advanced pulmonary fibrosis (FVC 40-50% predicted) for decline in forced vital capacity. Participants with the most rapid symp…
- USMLE Step 1 · hard24. A cohort study follows 82 year old adults with severe aortic stenosis to estimate time to hospitalization for heart failure. Many participants die from noncardiac causes before…