Class 18: Capture Recapture


A common method of estimating the number of fish in a lake or pond is the capture recapture method. In this method, c fish are caught, tagged, and returned to the lake. Later on, r fish are caught and checked for tags. Say t of them have tags. The numbers c, r, and t are used to estimate the fish poplulation.

Use capture recapture to estimate the number of Pepperidge Farm goldfish in a package. So that we can compare results, we ask that everyone capture and tag 50 goldfish initially, and then recapture 40. Since physically marking or tagging goldfish renders them unappetizing, Laurie prefers to replace the captured goldfish with pizza flavored goldfish instead. Linda doesn't mind eating magic marker. You can use whatever method of tagging you like.

Homework for Monday, April 1

Read Chapter 17 and do review exercises 1 - 11.

Journal Assignment for Wednesday, April 3

Read the article "Stalking HIV in the red light district" and the article "High Court Rules Results are Valid in Census of 1990". Comment in your journal.