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Standard deviationComparing data

Standard deviation is a measure of the spread of data around the mean value. It is used in comparisons of consistency between different data sets. Two formulae can be used to calculate this.

Part of Application of MathsStatistical skills

Comparing data

The mean and standard deviation are often used to compare two sets of data.

Example

Bob keeps annual records of daily temperatures.

In 1998 he found that the maximum daily temperature, in \(鈦癈\), in March had a mean of \(7.8\) and a standard deviation of \(4.2\).

In 2008 he found that the maximum daily temperature, in \(鈦癈\), in March had a mean of \(9.6\) and a standard deviation of \(1.5\).

Bob compares the data and states that:

  • the average daily temperature in March 2008 was warmer than in March 1998.
  • the daily temperatures in March 2008, were more consistent than in March 1998

Standard deviation

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