AO1 - Measures of Dispersion

• Measures of dispersion - This is based on the spread of scores: how far scores vary from the mean or range. For example, the range or standard deviation
• Range - The spread of data from the smallest to the largest, calculated by subtracting the lowest value from the highest value and adding 1

  • Used for ordinal data
• Standard deviation - Measure of spread around the mean

  • The higher the SD, the more the data is spread around the mean
  • The larger the calculated number, the data is spread around the mean, less consistency and more individual differences
  • The smaller the calculated number, the data is clustered around the mean so more consistency and less individual differences
  • Used for interval data