Measures of central tendency

• What is the central tendency of a data set

  This is the average or middle value
• What are the methods to measure central tendency

  Mean, median and mode
• What type of data is the mean used for

  Evenly or normally distributed data
• What type of data is the mode used for

  Nominal variables
• What type of data is the median used for and why

  It is referred to as a resistant measure meaning that it is not affected by outliers and so is often used for skewed data.
• What equation is this

  Sample mean.

  
• What equation is this

  Population mean

  
• What is x bar

  Sample mean
• Equation for X bar

  The sum of X / n. Where n is the number of units.
• Equation for mu

  Sum of X / N. Where N is the number of units.
• What is Mu

  Population mean
• What are the requirements to calculate the median


  The data must be ordered
• What measure of central tendancy is used in box plots

  Median
• Label this and say what it is

  It is a box plot.

  A) Maximum

  B) Q1

  C) Median

  D) Q3

  E) Maximum

  
• How do you calculate the IQR

  Q3 - Q1