Among men in a follow-up study, 3,151 were nondiabetic and 189 were diabetic. What is the ratio of nondiabetic to diabetic men?

1. A ratio divides the count in one group by the count in the other, so the nondiabetic count goes on top: 3,151 divided by 189. 2. 3,151 divided by 189 equals 16.67, which rounds to 16.7. 3. Ratios are usually rescaled so the denominator becomes 1, giving 16.7 to 1. 4. Turning the fraction over, 189 divided by 3,151, gives 0.06 to 1, the same comparison read backwards. 5. Putting the total of 3,340 men on top gives 17.7 to 1, and 189 out of 3,340 as a percentage gives 5.7, neither of which is the ratio asked for. _Source: CDC Principles of Epidemiology in Public Health Practice (3rd ed., US federal, public domain), Lesson 3 "Measures of Risk", section Method for calculating a ratio_