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2.4 Statistical Distributions

2.4 Statistical Distributions

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Question 204

The flight duration of a specialized cargo drone, TTT minutes, is modelled by a normal distribution with mean μ\muμ and standard deviation σ\sigmaσ. Given that μ=110\mu = 110μ=110 and σ=12\sigma = 12σ=12, use standardisation to:

a.

(i) show that P(T<95)=0.1056P(T < 95) = 0.1056P(T<95)=0.1056 (ii) calculate the value of t0t_0t0​ such that P(T<t0)=0.0228P(T < t_0) = 0.0228P(T<t0​)=0.0228

[5]
b.

An operator randomly monitors 3 independent drone flights.

Calculate the probability that each of the 3 flights lasts longer than 95 minutes.

[3]
c.

The drone's battery system is upgraded such that the new flight duration, XXX minutes, has mean μ=115\mu = 115μ=115 and standard deviation σ=s\sigma = sσ=s.

Given that P(X<x)=0.1587P(X < x) = 0.1587P(X<x)=0.1587 and P(X>1.4x−29)=0.0228P(X > 1.4x - 29) = 0.0228P(X>1.4x−29)=0.0228,

find the value of xxx and the value of sss.

[5]
Markscheme

2.4 Statistical Distributions Questions

  1. A Level
  2. /Maths
  3. /2.4 Statistical Distributions

390 exam-style questions on OCR A Level Maths 2.4 Statistical Distributions, covering 2.4.1 Discrete probability distributions, 2.4.2 Binomial distribution as a model, 2.4.3 Calculating binomial probabilities, 2.4.4 Mean and variance of the binomial (A-level only), 2.4.5 Normal distribution as a model (A-level only), 2.4.6 Probabilities using the normal distribution (A-level only), 2.4.7 Links to histograms, mean and standard deviation (A-level only), and 2.4.8 Selecting an appropriate distribution (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.

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