5.7 Describing Variability: The Standard Deviation - Video

Key Ideas

  • The variance, s2, of a set of observations is an average of the squared differences between the individual observations and their mean value.
  • The standard deviation, s, of a set of observations is the square root of the variance and measures the variability of the data about the mean in the same units of measurement as the original dataset. You should be instructed as to the method (spreadsheet, calculator with statistical capabilities, or by hand) required for calculating the variance and in turn the standard deviation.