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2.4 Statistical Distributions

2.4 Statistical Distributions

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Question 82

The weights of a breed of adult Labrador retrievers are normally distributed with mean 32.5 kg32.5\text{ kg}32.5 kg and standard deviation 2.4 kg2.4\text{ kg}2.4 kg.

a.

Find the probability that a randomly chosen Labrador of this breed weighs more than 30.1 kg30.1\text{ kg}30.1 kg.

[2]
b.

A puppy named Max is currently at the 70th70\text{th}70th percentile for weight in his age group.

Assuming Max remains at the 70th70\text{th}70th percentile, estimate his weight as an adult.

[3]
c.

The weights of adult Golden Retrievers are normally distributed with standard deviation 2.8 kg2.8\text{ kg}2.8 kg.

Given that 95%95\%95% of adult Golden Retrievers weigh more than the mean weight of the Labradors,

find the mean weight of an adult Golden Retriever.

[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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