Measures of Dispersion or Spread of Data

Range

The difference between the highest and lowest values

  • + Easy to calculate
  • – Affected by extreme values

Standard Deviation

The average distribution that each piece of data is from the mean for the group

  • + Takes each piece of data into account so very sensitive
  • + Allows us to make predictions about distributions if we know the mean and SD
  • – Harder and complex calculations