Question 2 of 4intermediate🔧 ApplyNumerical4 marks
An ornithologist wants to estimate the number of parrots in a large field. She uses a net to catch some, and catches 32 parrots, which she rings and sets free. The following week she manages to net 40 parrots, of which 8 are ringed.
(i)
What fraction of her second catch is ringed?
Answer
1/5
(ii)
Find an estimate of the total number of parrots in the field.
Answer
160 parrots
Explanation
This problem demonstrates the capture-mark-recapture method for population estimation. The key assumption is that the marked parrots mix uniformly with the remaining population, making the sample representative of the whole. The ratio of marked parrots in the second sample equals the ratio of marked parrots to total population in the field.