DESCRIPTIVE STATISTICS

• What is the mean?

  average of a set of numbers
• strength of the mean

  includes all the values in the data so represents the data
• weakness of mean

  may be unrepresentative as one very large or small number can distort the values
• what is the median?

  middle value in a set of numbers
• strength of the median

  less affected by extreme scores as the median is only focused on the middle value
• weakness of median

  less sensitive than the mean as the higher and lower numbers are ignored but extreme values may be important
• what is the mode?

  most frequent or common value
• strength of the mode

  relevant to categorical data
• weakness of the mode

  overly simple measure
• what are the three measures of central tendency?

  Mean

  Median

  Mode
• what are the measures of dispersion?

  range

  standard deviation
• what is the range?

  difference between highest and lowest values in a set of data
• strength of the range

  easy to calculate
• weakness of the range

  does not account for the distribution of the scores
• what is standard deviation?

  measure of the average spread around the mean, the larger the SD the more spread out the data is
• strength of standard deviation

  more precise than the range as it includes all values within the calculation