Descriptive statistics

• Mean

  • Add all of the scores up and divide by the number of scores there are.
• Median

  • line all of the scores up in order.
  • Select the middle score
• Mode

  • Select the most common/occurring score in a set of data
• Range

  • Represents spread
  • Tells us whether a set of data are close together or spread out
  • Arrange data in order and subtract lowest from highest score
• Evaluation of range

  Strength

  • Easy to calculate

  Weakness

  • Distorted by extreme scores
  • For example, in the set 5,6,7,8,100 the range would be 95 (100 - 5), which suggests a large spread, even though most values are close together
• Evaluation of mean

  Strength:

  • Uses all the data, so most representative measure
  • in balanced datasets

  Weakness:

  • Distorted by extreme scores so less reflective of the typical value
• Median

  Strength

  • Not effected by extreme scores.

  Weakness

  • Does not include all scores so less representative than the mean
• Mode

  Strength

  • Very easy to calculate
  • Weakness:
  • Not representative of all data