Editing Mark and recapture (section)

== Notation ==
Let
: ''N'' = Number of animals in the population
: ''n'' = Number of animals marked on the first visit
: ''K'' = Number of animals captured on the second visit
: ''k'' = Number of recaptured animals that were marked

A biologist wants to estimate the size of a population of turtles in a lake.  She captures 10 turtles on her first visit to the lake, and marks their backs with paint. A week later she returns to the lake and captures 15 turtles.  Five of these 15 turtles have paint on their backs, indicating that they are recaptured animals. This example is (n, K, k) = (10, 15, 5). The problem is to estimate ''N''.