Measures of Central Tendency (DP IB Applications & Interpretation (AI)): Revision Note

Mean, Mode, Median

What are the mean, mode and median?

• Mean, median and mode are measures of central tendency

  • They describe where the centre of the data is

• They are all types of averages

• In statistics it is important to be specific about which average you are referring to

• The units for the mean, mode and median are the same as the units for the data

How are the mean, mode, and median calculated for ungrouped data?

• The mode is the value that occurs most often in a data set

  • It is possible for there to be more than one mode

  • It is possible for there to be no mode

    • In this case do not say the mode is zero

• The median is the middle value when the data is in order of size

  • If there are two values in the middle then the median is the midpoint of the two values

• The mean is the sum of all the values divided by the number of values
  

  
  

  • Where  is the sum of the n pieces of data

  • The mean can be represented by the symbol μ

• Your GDC can calculate these statistical measures if you input the data using the statistics mode