Measures of spread

• Range is the difference between the smallest and largest values of a data set:
  \[ \mbox{Range} = \mbox{Maximum value} - \mbox{Minimum value} \]
• The range can be misleading when outliers are present.
• The interquartile range is the difference between the third quartile and the first quartile.
• The standard deviation is the average of the differences from the mean.