Descriptive statistics

• What are descriptive statistics?


  express numbers in a way that shows the overall pattern
• range

  spread of data

  arrange data in order and subtract lowest from highest score
• strengths of range

  Easy to calculate
• weaknesses of range

  can be distorted by extreme scores
• mean


  mathematical average

  add up all the numbers and divide by the number of scores
• strengths of mean

  uses all the data, so must sensitive measure
• weaknesses of mean

  can be distorted by extreme values
• median


  middle value

  data put in order from lowest to highest
• strengths of median

  not effected by extreme scores
• weaknesses of median

  less sensitive than the mean to variation in values
• mode

  most common score(s)
• strengths of mode

  -Very easy to calculate

  -Unaffected by extreme values
• weaknesses of mode

  can be unrepresentative