Denominator in sensitivity is ?

Ans. is 'b' i.e., Total number of diseased people i) SensitivityIt is the percentage of diseased people that who are diagnosed as having disease.Total number of diseased people = True positive + False negative.Number of people (among diseased people) diagnosed as having disease = True positives. ii) SpecificityIt is the percentage of healthy people who are identified as healthy.Total number of healthy people = True negatives + False positivesNumber of healthy people who are identified as healthy = True negatives