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2 Statistics

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Question 172

A café serves two types of drinks: Large, LLL, and Standard, SSS. The volumes, in ml, of Large drinks are distributed as L∼N(500,152)L \sim \text{N}(500, 15^2)L∼N(500,152) and Standard drinks are distributed as S∼N(330,82)S \sim \text{N}(330, 8^2)S∼N(330,82).

A Large drink and a Standard drink are selected at random.

a.

Find the probability that the volume of the Large drink is less than 150% of the volume of the Standard drink.

[4]
b.

Two Standard drinks are chosen at random.

Find the probability that their volumes differ by more than 10 ml.

[4]
c.

The café sells drinks in trays. Each tray contains either 4 Large drinks or 6 Standard drinks. The weight of an empty tray, TTT, is distributed as T∼N(100,52)T \sim \text{N}(100, 5^2)T∼N(100,52). We assume 1 ml of drink weighs 1 g.

Find the probability that a tray of 6 Standard drinks weighs more than a tray of 4 Large drinks.

[5]
Markscheme

2 Statistics Questions

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

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