What is 1.5 per million?

1.5 per million refers to a ratio or a rate indicating that for every million units or individuals, there are 1.5 instances of a particular event or characteristic. This can be expressed as a fraction, such as 1.5/1,000,000, or as a percentage, which is 0.00015%. It is often used in epidemiology, statistics, and other fields to convey the prevalence of an occurrence in a large population.