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2 Statistics

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Question 74

The masses of lithium-ion battery packs, B B\,B grams, are distributed such that B∼N(450,152)B \sim \text{N}(450, 15^2)B∼N(450,152).

Five battery packs are selected at random.

a.

Calculate the probability that their total mass exceeds 2280 g.

[3]
b.

The masses of industrial sensors, S S\,S grams, are such that S∼N(85,42)S \sim \text{N}(85, 4^2)S∼N(85,42).

Two sensors are selected at random.

Calculate the probability that the magnitude of the difference in their masses is more than 5 g.

[3]
c.

The masses of protective housing units, H H\,H grams, are such that H∼N(1200,160)H \sim \text{N}(1200, 160)H∼N(1200,160).

The random variable A A\,A represents the total mass, in g, of a single housing unit packed with 10 sensors, where A A\,A and H H\,H are independent.

Calculate P(A>0.9H+950)P(A > 0.9H + 950)P(A>0.9H+950).

[4]
Markscheme

2 Statistics Questions

  1. A Level
  2. /Maths
  3. /2 Statistics

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