Anyways,
the sample is the 100 trees checked. Thats cause they checked all 100 and found 24 had damage. Which means they sampled 100 trees out of the whatever amount in the forest.
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[SEPARATE QUESTION]
Separate question since people are confused about it in the previous answers comments "Which of the following statements best describes the bias that may arise from the results?":
I can confirm A is wrong. C just, feels wrong completely.
So that leaves us with B or D.
I think it's D: Trees near the road may have more damage than trees away from it, so the results may overestimate the overall damage of the trees.
I have not finished yet but I am 95% sure D is correct.
The reason why I don't believe it's B is because they want to resample near the same road, which can still result to biased results.
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ED2021