AQA S1 2014 June — Question 2 3 marks

Exam BoardAQA
ModuleS1 (Statistics 1)
Year2014
SessionJune
Marks3
TopicNormal Distribution
TypeMixed calculations with boundaries

2 A garden centre sells bamboo canes of nominal length 1.8 metres. The length, \(X\) metres, of the canes can be modelled by a normal distribution with mean 1.86 and standard deviation \(\sigma\).
  1. Assuming that \(\sigma = 0.04\), determine:
    1. \(\mathrm { P } ( X < 1.90 )\);
    2. \(\mathrm { P } ( X > 1.80 )\);
    3. \(\mathrm { P } ( 1.80 < X < 1.90 )\);
    4. \(\mathrm { P } ( X \neq 1.86 )\).
  2. It is subsequently found that \(\mathrm { P } ( X > 1.80 ) = 0.98\). Determine the value of \(\sigma\).
    [0pt] [3 marks]
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