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2.4 Statistical Distributions

2.4 Statistical Distributions

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Question 60

A random sample of size $n\,$ is taken from a population that is normally distributed with mean 25 and standard deviation 4.

Find the smallest value of $n\,$ for which the probability that the sample mean is greater than 27.5 is less than 1%.

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Markscheme

2.4 Statistical Distributions Questions

A Level
Maths
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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