Epidemiology for Public Health Practice 5th Edition by Robert Friis,Thomas Sellers

Exercise 4

Assume that the fasting blood level of a lipid is normally distributed in the population of people who do not have disease "X." There is a smaller distribution curve of the fasting blood levels of this lipid, which also is normal in shape, for the population of persons who have disease "X," and the curve overlaps the upper end (right side) of the curve for people without the disease. Draw distribution curves for the diseased and nondiseased populations and discuss the effects upon sensitivity and specificity of setting the cut point for disease and nondisease at various positions on the two overlapping curves.