Estimating populations

Question 1

Mark and recapture #1

Answer 1

M/N=r/s

M = the number of animals marked and released
N = the size of the population
r = the number of marked animals re-captured in the second sample
s = the size of the second sample including both marked and unmarked animals.

Question 2

Mark and recapture #2

Answer 2

N=s/r*M

M = the number of animals marked and released
N = the size of the population
r = the number of marked animals re-captured in the second sample
s = the size of the second sample including both marked and unmarked animals.

Question 3

Assumptions

Answer 3

1. Marked are randomly mingled with the rest of the population.
2. Losses from or gains to the population due to deaths, births, immigration, or emigration between sampling periods are negligible.
3. All individuals are equally likely to be caught.
4. Marking does not affect the individuals.
5. Samples are taken randomly.

Question 4

Percent error

Answer 4

Difference/Actual*100