Measures of central tendency

• What are measures of central tendency?

  Used to summarise large amounts of information into summaries.
• What does the mean measure?

  Interval data only.
• What does the median measure?

  Ordinal and interval data only.
• What does the mode measure?

  The most useful for nominal data.
• What is a strength of the mean?

  More sensitive than the median because it makes use of all the values of data.
• What is a weakness of the mean?

  It can be misrepresentative if there is an extreme value.
• What is a strength of the median?

  It is not affected by extreme scores, so can give a representative value.
• What is a weakness of the median?

  It is less sensitive than the mean as it does not take into account all the data values.
• What is a strength of the mode?

  It is useful when the data are in categories, such as the number of babies who are securely attached.
• What is a weakness of the mode?

  It is not a useful way of describing data when there are several modes.