Estimate Population Size

You catch, tag, and release 50 fish back into a pond. Then, you catch 25 more fish, 5 of which are tagged. What is the best estimate of the number of fish in the pond?

• 100 fish

• 250 fish

• 400 fish

• 625 fish

A pond contains two kinds of fish, trout and bass, of which 20% are bass and 80% are trout. If you catch 5

fish at random from this pond, which would you expect to catch?

• 0 bass and 5 trout

• 1 bass and 4 trout

• 4 bass and 1 trout

• 5 bass and 0 trout

A pond contains 1000 fish, 100 of which have been tagged. You catch 10 fish. How many of the fish would you expect to be tagged?

• 0

• 1

• 5

• 10

Pond 1 contains 100 fish, 50 of which are tagged. Pond 2

contains 1000 fish, 500 of which are tagged. You catch 10

fish from each pond. Which statement is true?

• There should be more tagged fish in the catch from Pond 1

• There should be more tagged fish in the catch from Pond 2

  .

• The catches from both ponds should have about the same number of tagged fish.

• The most likely result is that there will be no tagged fish in either catch.

What usually happens to the accuracy of an estimate of population size as the number of fish caught increases?

• The estimate is usually more accurate.

• The estimate is usually less accurate.

• The accuracy of the estimate will not change.

• The estimate is most accurate when the number of fish caught is 50% of the total population.