A-level · Statistical distributions

The normal distributionExam-style questions

The normal model N(μ, σ²) for continuous data — its symmetric bell shape, mean = median = mode = μ, spread set by σ, and standardising any normal variable to the standard normal Z = (X − μ)/σ.

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16 questions · A-level level · mark scheme and worked solution on each · no sign-up to try

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1
The mass $X$ kg of an item is modelled by $X \sim N(60, 64)$ . Write down the mean and the standard deviation of $X$ .
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2
$X \sim N(20, 25)$ . Approximately $95\%$ of values lie within two standard deviations of the mean. Between which two values is this?
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