Numerical measures

• Advantages of using the mean


  • influenced equally by each value
  • appropriate for large samples and symmetric data
• Disadvantages of using the mean


  • may be skewed by one value in a small sample
• Advantages of using the mode


  • easy to find
• Disadvantages of using the mode


  • may be more than one
  • may not be useful
• Advantages of using the median


  • not all values are needed to find it
  • less affected by skew
• Disadvantages of using the median


  • difficult to identify in a large sample
• Advantages of using the range


  • easy to calculate
• Disadvantages of using the range


  • influenced by one significant value
• Advantages of using the IQR


  • not influenced by unusual values
  • less affected by skew
  • easy for small sample sizes
• Disadvantages of using the IQR


  • difficult with large sample sizes and no technology
• Advantages of using standard deviation


  • influenced equally by each piece of data
  • more appropriate for large samples or symmetrical data
  • very useful for statistical modelling
• Disadvantages of using standard deviation


  • more complicated than other measures if no technology
  • difficult with large samples