To estimate the number of bass in a lake, a biologist catches and tags 30 bass. Several weeks later, the biologist catches a new sample of 44 bass and finds 3 are tagged. How many bass are in the lake?

Use the Lincoln-Petersen estimator.

N = Kn/k

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N = animals in population

n = number of animals marked first visit

K = number animals captured second visit

k = number recaptured animals that were marked

I have used this estimator many times. Fairly accurate.