Delaware's infant mortality rate in 2001 was 10.7 per 1,000 live births and New Hampshire's was 3.8 per 1,000. What is the ratio of the two rates?

1. Rates can form the numerator and denominator of a ratio just as counts can. 2. Divide the Delaware rate by the New Hampshire rate: 10.7 divided by 3.8 equals 2.816. 3. Rounded to one decimal place that is 2.8, reported as 2.8 to 1. 4. Subtracting instead of dividing gives 6.9, which is a difference in rate, not a ratio. 5. Adding gives 14.5 and inverting gives 0.4, so both of those describe something other than Delaware relative to New Hampshire. _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_