Statistics › Sampling and inference › Capture-recapture estimates
Fish population by tag and recapture
High school · ●●○○○ 20 pts
A biologist wants to estimate the number of fish in a lake. On May 1 she catches a random sample of 60 fish, tags them, and releases them. On September 1 she catches a random sample of 70 fish and finds that 3 of them are tagged. To estimate the number of fish in the lake on May 1, she assumes that 25% of the May 1 fish are no longer in the lake on September 1 (because of death and emigration), that 40% of the fish in the lake on September 1 were not in the lake on May 1 (because of births and immigration), and that the tagged and untagged fish in the September 1 sample are representative of the whole population. What number does she calculate for the number of fish in the lake on May 1?