This topic is taught through its practice: 12 practice questions, each with the reasoning behind the answer, and the same idea again in plain words.
Quick check
5 questions here, of 12 in this lesson’s practice set. Answers stay hidden until you check.
Question 1 of 5foundational
A screening test is administered to 100 people who are already known (by a gold-standard reference test) to have a particular condition. Ninety of them test positive. Which term and value correctly describe this result?
Choose an answer, then check it.
Question 2 of 5foundational
A new test is evaluated in two verified groups: among 60 people who truly have the condition, 48 test positive; among 250 people confirmed to be free of the condition, 225 test negative. What is the specificity of the test?
Choose an answer, then check it.
Question 3 of 5foundational
In a hypothetical cohort, 400 healthy volunteers are followed for one year and 100 of them develop the outcome of interest. Which term and value best describe the quantity 100/400?
Choose an answer, then check it.
Question 4 of 5intermediate
In a hypothetical cohort study, 15 of 300 exposed participants and 5 of 500 unexposed participants develop the outcome. Which statement correctly expresses the relative risk (risk ratio)?
Choose an answer, then check it.
Question 5 of 5intermediate
In a hypothetical trial, the outcome occurred in 30 of every 100 people in the control group and 20 of every 100 people in the intervention group. Approximately how many people must receive the intervention to prevent one additional occurrence of the outcome?
