NBME CBSE: PUBLIC HEALTH SCIENCES PT.1 ACTUAL

NBME CBSE: PUBLIC HEALTH SCIENCES PT.1 (ACTUAL

QUESTIONS AND VERIFIED ANSWERS GRADED A+

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What does a better performing test have in terms of the ROC curve? - ---Answers---Higher area under the curve (AUC) and closer to the upper left corner

What is precision? - ---Answers---Consistency and reproducibility of a test

What decreases precision? - ---Answers---Random variation or random error

What happens when precision increases? - ---Answers--- Lower standard deviation (SD) and higher statistical power (beta)

What is accuracy? - ---Answers---Closeness of test results to true values

What decreases accuracy? - ---Answers---Systematic error or bias in a test

What is incidence? - ---Answers---Number of new cases divided by the number of people at risk 1 / 3

What is prevalence? - ---Answers---Number of existing cases divided by the number of people in the population

What is the formula for calculating prevalence? - ---Answers- --Prevalence = incidence rate * average duration of disease / (1 - prevalence)

What happens to prevalence with an increase in prevalence? - ---Answers---Increase in positive predictive value (PPV) and decrease in negative predictive value (NPV)

What happens to incidence and prevalence with increased survival time? - ---Answers---No incidence and high prevalence

What happens to incidence and prevalence with high mortality?

• ---Answers---No incidence and low prevalence

What happens to incidence and prevalence with faster recovery time? - ---Answers---No incidence and low prevalence

What is extensive vaccine administration? - ---Answers--- Low incidence and prevalence

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What are low risk factors? - ---Answers---Low incidence and prevalence

What is high diagnostic sensitivity? - ---Answers---High incidence and prevalence

What happens when a new effective treatment is started? - --- Answers---No incidence and low prevalence

What is low contact between infected and non-infected patients with airborne infectious disease? - ---Answers--- Low incidence and prevalence

What is selection bias? - ---Answers---Nonrandom sampling or treatment allocation that makes the study population not representative of the target population

What is convenience sampling? - ---Answers---Enrolling patients based on ease of contact

What is Berkson bias? - ---Answers---Cases and/or controls selected from hospitals that are less healthy and have different exposures

What is attrition bias? - ---Answers---Participants lost to follow-up have a different prognosis than those who complete the study

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