Paper081. A new GP dermoscopy rule is tested on 200 lesions. 40 are melanoma; the rule flags 32 of those 40, and also flags 24 of 160 non-melanomas. What is sensitivity?A. 32/40 = 80%B. 32/56 in this NHS general-practice settingC. 24/160 in this NHS general-practice settingD. 32/200 in this NHS general-practice settingCheck
Paper082. From the same table (32 TP, 24 FP), what is PPV?A. 32/40B. 136/160C. 32/(32+24) = 57%D. 32/200Check
Paper083. True negatives 136, false negatives 8. NPV? Select TWO correct statements.Select all that apply.A. Most appropriate: 136/(136+8) = 94.4%B. The following is not the most appropriate next step: 136/160C. Most appropriate: 8/40 in this NHS general-practice settingD. Most appropriate: 32/56 in this NHS general-practice settingCheck
Paper084. A very specific test (Sp 99%) is used to ‘screen’ a condition with prevalence 0.1%. What happens to PPV?A. PPV equals specificity always in this NHS general-practice setting which is not the safest next step in NHS general practiceB. Sensitivity becomes 99% automatically in this NHS general-practice setting which is not the safest next step in NHS general practiceC. PPV is still low because prevalence is tiny — high specificity does not guarantee a high PPV in rare diseaseD. Prevalence does not affect PPV in this NHS general-practice setting which is not the safest next step in NHS general practiceCheck
Paper085. Investigators randomly allocate 200 people with Parkinson’s to physiotherapy A vs B and measure UPDRS at 12 weeks. Design?A. Case–controlB. Qualitative ethnography in this NHS general-practice settingC. Diagnostic 2×2 without a reference standard as the primary design in this NHS general-practice settingD. Randomised controlled trialCheck
Paper086. A dementia-drug trial recruits only from a private memory clinic that excludes vascular disease. External validity? Select TWO correct statements.Select all that apply.A. Most appropriate: Selection bias / limited generalisability to typical NHS mixed dementiaB. The following is not the most appropriate next step: Perfect external validityC. Most appropriate: This is only recall bias in this NHS general-practice settingD. Most appropriate: Randomisation of clinics is automatic in this NHS general-practice settingCheck
Paper087. A case–control study of migraine and childhood diet relies on 40-year-old food memories. Main bias? Select TWO correct statements.Select all that apply.A. Most appropriate: Recall bias in this NHS general-practice setting in this NHS general-practice settingB. The following is not the most appropriate next step: Observer-expectancy from unblinded outcome assessors onlyC. Most appropriate: Lead-time bias in this NHS general-practice setting in this NHS general-practice settingD. Most appropriate: Length-time bias in this NHS general-practice settingCheck
Paper088. Relative risk 0.82, 95% CI 0.61 to 1.10. Interpretation? The most appropriate action is: Proves no effect of any sizeTRUE. TrueFALSE. FalseCheck
Paper089. Mean BP difference −8 mmHg, 95% CI −12 to −4. Interpretation?A. A reduction of between 4 and 12 mmHg is compatible with the data at 95% confidence; the interval excludes 0B. The CI crossing 0 in this NHS general-practice setting which is not the safest next step in NHS general practiceC. No effect is possible in this NHS general-practice setting which is not the safest next step in NHS general practiceD. This is a ratio crossing 1 in this NHS general-practice setting which is not the safest next step in NHS general practiceCheck
Paper0810. A neuro-oncology screening test finds gliomas earlier; survival from diagnosis lengthens but death dates do not change. Bias? The most appropriate action is: Overdiagnosis only as the only nameTRUE. TrueFALSE. FalseCheck