measures of central tendency

• Measures of central tendency

  • Mean
  • Median
  • Mode
• mean

  • arithmetic average, add up all the scores and divide by the number of scores.
  • Strength = sensitive measure
  • includes all scores/measures in the data set - represents data set better than median or mode
  • Limitation = may be unrepresentative
  • Final average easily distorted by one very large/small number
• median

  • middle value, place scores in ascending order and select middle value - if there are two values in the middle, the mean of these is calculated
  • Strength = less affected by extreme scores
  • Limitation = less sensitive than the mean
  • Extreme values may be important
• mode

  • most frequent or common value, used with categorical/nominal data.
  • Strength = relevant to categorical data
  • When data is discrete (eg represented in categories) - sometimes mode is only appropriate measure
  • Limitation = overly simple measure
  • Mode may be at one extreme - not useful way of describing data when there are many modes