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3.5 Finding the mean and standard deviation

3.5 Finding the mean and standard deviation

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Question 43

An agricultural scientist monitors the daily yield of milk, in litres, from a herd of cows at a local farm. The daily yield in the spring, S S\,S litres, can be modelled by a normal distribution S∼N(800,602)S \sim \text{N}(800, 60^2)S∼N(800,602).

a.

Using standardisation and showing your working, find the probability that, on a randomly selected day in the spring,

(i) more than 710 litres of milk is produced,

(ii) 800 litres of milk, correct to the nearest 40 litres, is produced.

[5]
b.

The daily milk yield in the winter, W W\,W litres, can be modelled by W∼N(μ,σ2)W \sim \text{N}(\mu, \sigma^2)W∼N(μ,σ2).

Given that P(W>745)=0.1056\text{P}(W > 745) = 0.1056P(W>745)=0.1056 and P(W<580)=0.25\text{P}(W < 580) = 0.25P(W<580)=0.25,

(i) find two equations in terms of μ \mu\,μ and σ\sigmaσ,

(ii) hence, showing your working, find the value of μ \mu\,μ and the value of σ\sigmaσ.

[6]
Markscheme

3.5 Finding the mean and standard deviation Questions

  1. A Level
  2. /Maths
  3. /3.5 Finding the mean and standard deviation

48 exam-style questions on Edexcel A Level Maths 3.5 Finding the mean and standard deviation. Each one has a worked solution and a mark scheme showing where the marks go.

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