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Measures of spread

Standard deviation

  • The standard deviation is the most widely used measure of spread associated with the mean.
  • The standard deviation is the average of the differences from the mean.
  • To calculate the sample standard deviation:
    \[s = \sqrt{\frac{\Sigma (x_i-\bar{x})^2}{n-1}}\]
  • Standard scientific calculators allow you to calculate the sample standard deviation.

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