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2.4 Statistical Distributions

2.4 Statistical Distributions

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Question 221

The life of a certain type of battery, BBB hours, is normally distributed with a mean of 120 hours and a standard deviation of 16 hours.

a.

Find P(B>144)P(B > 144)P(B>144).

[2]
b.

Find the value of kkk such that P(B<k)=0.15P(B < k) = 0.15P(B<k)=0.15.

[3]
c.

Ben is preparing for a 12-hour recording session. Given that the battery has already been in use for 144 hours,

find the probability that the battery will not run out before the session is completed.

[4]
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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