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2.4 Probability Distributions

2.4 Probability Distributions

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Question 258

A botanical research lab collects soil samples for analysis. The weight of an individual soil sample, SSS, is modelled by a normal distribution with mean 4.12 kg and standard deviation 0.15 kg.

a.

Find the probability that the weights of two randomly selected soil samples differ by more than 0.25 kg.

[4]
b.

Soil samples are grouped and placed into storage bins for transport. The weight of an empty storage bin, BBB, is modelled by a normal distribution with mean 15.4 kg and standard deviation 1.40 kg.

Each fully loaded storage bin contains 30 soil samples.

Find the probability that the total weight of a randomly selected fully loaded storage bin is less than 136.5 kg.

[4]
Markscheme

2.4 Probability Distributions Questions

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

390 exam-style questions on OCR (MEI) A Level Maths 2.4 Probability Distributions, covering 2.4.1 Recognise binomial situations, 2.4.2 Probability of success p, 2.4.3 Calculate binomial probabilities, 2.4.4 Mean of the binomial distribution, 2.4.5 Expected frequencies for binomial, 2.4.6 Probability functions and discrete random variables, 2.4.7 Numerical probabilities for a simple distribution, 2.4.8 Normal distribution as a model (A-level only), 2.4.9 Shape of the Normal curve (A-level only), 2.4.10 Linear transformation and standardising (A-level only), 2.4.11 Symmetry and inflection of Normal curve (A-level only), 2.4.12 Calculate probabilities from a Normal distribution (A-level only), 2.4.13 Model with probability distributions, and 2.4 Probability Distributions. Each one has a worked solution and a mark scheme showing where the marks go.

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