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 specificity Sp as a percentage. 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 positive predictive value PPV as a percentage. Round to one decimal place.
Practice exercise (made-up values, not clinical guidance). In a randomised trial, 420 patients received a new treatment and 630 received the control treatment. The table shows how many in each group had the outcome (an unwanted event such as a stroke). Find the number needed to treat NNT to prevent one event. Round up to a whole number of patients.
Practice exercise (made-up values, not clinical guidance). A test has a sensitivity of 83% and a specificity of 80%. Find the positive likelihood ratio LR+. Round to two decimal places.
Practice exercise (made-up values, not clinical guidance). Without a drug, 25% of patients have a certain side effect during a year. The drug raises this risk with a relative risk of RR = 1.91. Find the number needed to harm NNH: how many patients must take the drug for a year for one extra patient to have the side effect? Round up to a whole number of patients.
Practice exercise (made-up values, not clinical guidance). 10 000 people are screened with a test of sensitivity 92% and specificity 76%. The prevalence of the disease is 13%. How many people with the disease are missed by the test (false negatives, FN)?
Full step-by-step solutions: practise this topic on examproblems.com.