Central Tendency

• How to calculate mean?

  add up and divide by number of data points
• advantages of MEAN?


  • uses all data in calculation
  • most accurate measure of central tendency
• why is the mean the most accurate measure of central tendency?

  Uses interval level of measurement when the units of measurement are all of equal size
• give one -ive of mean?

  less useful if there is an extreme score which will then skew the data
• give one -ive of mean?

  the mean score could be one that isnt actually listed in your data set which can create difficulties when applying to people
• 2 brief -ives of mean?

  • could be one which is not listed
  • extreme scores- skew the data
• what is the median?

  The central score in a list of rank ordered scores
• when is the median the middle number?

  with an odd number of scores
• when is the median the mid point between the 2 middle scores?


  with an even number of scores
• median brief advantages?


  • not affected by extreme scores
  • usually easier to calculate than the mean
  • can be used with ordinal (ranked) data but the mean cannot
• median -ives (brief)?


  • not as representative/sensitive as mean
  • small sets of data- can be unrepresentative
• median -ive?


  Not as sensitive/representative as the mean (as not all scores are used in its description you only quote one score)
• median -ive?


  can be very unrepresentative of small sets of data
• what is the mode?

  the most common or popular score
• brief positives of mode?

  • less prone to distortion
  • makes more sense than mean
• positive of mode?


  less prone to distortion/extreme value
• positive of mode?


  makes more sense than the mean
• give the ONE disadvantage of MODE?

  Can be more than ONE mode in a given set of data
• Strength of median?


  Not affected by extreme scores
• Strength of median?


  Usually easier to calculate than the mean
• strength of median?


  can be used with ordinal (ranked) data but the mean cannot