DESCRIPTIVE STATISTICS

• Measures of central tendency:

  • MIDDLE of the data set

  EXAMPLES:

  • MEAN
  • MEDIAN
  • MODE
• Measures of dispersion:

  • SPREAD of DATA around a CENTRAL VALUE
• Mean:

  • Takes all numbers into account 
  • Includes extreme values
• Median:

  • Unaffected by extreme values
• Mode:

  • Can get many modes 
  • Only measure of central tendency that can be used for qualitative data 
• MEASURES OF DISPERSION:

  • SPREAD of DATA around a CENTRAL value

  EXAMPLES:

  • RANGE
  • STANDARD DEVIATION
• Range:

  • Highest score - Lowest score
  • It is quicker / easier to calculate than the SD
  • Not always representative 
  • Sensitive to anomalies
• Standard Deviation (SD) 

  • Calculates the spread of scores around the mean
  • Lower- values are closer to the mean
  • Higher- values are more spread out 
  • More time-consuming to calculate than the range
  • Can only be calculated when the data has a mean
  • Most representative and precise