Wildlife preservers caught some tigers, tagged and released them. They later caught a second sample of exactly the same size and found that 10% of tigers had tags. According to their calculations , approx 2000 tigers were in the forest. How large was the sample of tigers that they collected.
2 Answers | Add Yours
We assume that the samples taken are completely random.
Then the original sample was one tenth of the population. (They tagged some percentage of the total population -- the next random sample of the same size found 10% had been sampled before, so the tagged specimens are 10 percent of the population.)
Thus the sample sizes are 2000/10=200.
These problems are solved with proportions. Normally, you would solve for how many total animals are there. But, that's ok. The formula:
how many total tags/how many total animals =
how many tags you "recatch"/how many animals you recatch
These ratios have to be equal. We know know "how many total animals", 2000. We also know that the right ratio would be 1/10 (for 10%, 10% of the "recatch" had tags). So:
x/2000 = 1/10
10x = 2000
x = 200
So, there were 200 animals who were tagged.
Join to answer this question
Join a community of thousands of dedicated teachers and students.Join eNotes