The burst altitude of SkyBound meteorological balloons, HHH metres, is normally distributed with mean 32,000 metres and standard deviation 1,400 metres.
(i) Find P(H≠32000)P(H \neq 32000)P(H=32000).
(ii) Find P(30000<H<35000)P(30000 < H < 35000)P(30000<H<35000).
Determine the altitude exceeded by 70% of SkyBound balloons.
A competing brand, AeroVantage, has a burst altitude YYY metres modelled by a normal distribution with mean 28,000 metres and standard deviation σ\sigmaσ. Given that 18% of randomly selected AeroVantage balloons burst below 26,000 metres, find the value of σ\sigmaσ, correct to three significant figures.
228 exam-style questions on CCEA A Level Maths 4.5.1 Statistical distributions (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.