Biologists want to know how many fish are in a certain lake. On January 1, they removed 730 fish from the lake and tagged them. On February 1, they returned to the lake and collected a random sample of 380 fish, of which 40 had been previously tagged. How many fish does the lake have, based on this experiment?

Question

Israel Richmond

Mathematics

29 January, 18:50

Biologists want to know how many fish are in a certain lake. On January 1, they removed 730 fish from the lake and tagged them. On February 1, they returned to the lake and collected a random sample of 380 fish, of which 40 had been previously tagged. How many fish does the lake have, based on this experiment?

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Answers (1)

Know the Answer?

Alexia Galvan · Answer 1

Intuitive way: by proportion

Let x=population size.

then

x/730 = 380/40

solve for

x = (380/40) * 730

=6935

Can also be solved using a hypergeometric distribution using a maximum likelihood estimate. Gives identical result in this case.