Practice exercise (made-up values, not clinical guidance). A town has 14 000 inhabitants. At the start of a year, 312 of them have a chronic disease. During the year, 135 more people are newly diagnosed (assume nobody moves away or dies). Find the cumulative incidence CI over the year per 1000 people at risk. Round to one decimal place.
Practice exercise (made-up values, not clinical guidance). A new test was compared with the reference standard in a study (see the 2 × 2 table). Find the negative predictive value NPV as a percentage. Round to one decimal place.
Practice exercise (made-up values, not clinical guidance). A test has a sensitivity of 90% and a specificity of 86%. Find the negative likelihood ratio LR−. Round to two decimal places.
Practice exercise (made-up values, not clinical guidance). In a cohort, groups of people were followed for different lengths of time (see the table: number of people and years of follow-up for each). During follow-up, 146 new cases occurred. Find the incidence rate IR per 1000 person-years. Round to one decimal place.
Practice exercise (made-up values, not clinical guidance). A patient has a pre-test probability of 20% for a disease. A test with sensitivity 83% and specificity 81% comes back negative. Find the post-test probability p′ of the disease as a percentage. Round to one decimal place.
Practice exercise (made-up values, not clinical guidance). 10 000 people are screened with a test of sensitivity 74% and specificity 77%. The prevalence of the disease is 5%. How many true-positive results TP are expected?
Full step-by-step solutions: practise this topic on examproblems.com.