Probability & Statistics 2 — Variant 3
A Level Mathematics · 9709/63 · Oct/Nov 2022
Questions
3 of 7 questions shown here, checked against the paper. The others are in the PDF above — they contain diagrams or maths we could not yet verify, and we would rather show you the original than a transcription we are not sure of.
1
[3]
The heights, in metres, of a random sample of mature trees of a certain variety are given below. Find unbiased estimates of the population mean and variance of the heights of all mature trees of this variety.
3
Drops of water fall randomly from a leaking tap at a constant average rate of per minute.
3(a)
[3]
Find the probability that at least drops fall during a randomly chosen -second period.
3(b)
[4]
Use a suitable approximating distribution to find the probability that at least drops fall during a randomly chosen -hour period.
5
A builders' merchant sells stones of different sizes.
5(a)
[3]
The masses of size stones have standard deviation grams. The mean mass of a random sample of size stones is grams. Find a confidence interval for the population mean mass of size stones.
5(b)
[4]
The masses of size stones have standard deviation grams. Using a random sample of size , an confidence interval for the population mean mass is found to have width grams. Find .
Published by Cambridge Assessment International Education. Reproduced for study use.