MATM 2

• Measure of central tendency


  To describe a whole set of data with a single value that represents the middle or centre of its distribution
• Central tendency


  A way to describe the center of a data set
• Central tendency importance


  • It lets us know what is normal or 'average' for a set of data
  • It condenses the data set down to one representative value, useful when working with large amounts of data
  • Allows comparison of one data set to another and one piece of data to the entire data set
• Main measures of central tendency

  • Mean or Arithmetic mean or average
  • Median
  • Mode
• Mean or Arithmetic mean


  The sum of all values in the observation or dataset divided by the total number of observations
• Mean or Arithmetic mean influence

  • Influenced by outliers and skewed distributions
  • Applicable for ratio and interval data
• Mean can be used for both continuous and discrete numeric data as well as for categorical data
• Find the mean


  Sum all values and divide by the total number of observations
• Median


  The physical middle point in a distribution, dividing the distribution in half when values are arranged in ascending or descending order
• Median importance


  • Preferred measure of central tendency when the distribution is not symmetrical
  • Less affected by outliers and skewed data than the mean
  • Widely used for ordinal type of information
• Median cannot be identified for categorical nominal data
• Find the median


  Arrange values in ascending or descending order, then find the one in the center
• Mode


  The most commonly occurring value in a distribution
• Mode limitations


  • There can be more than one mode (bi-modal, or multi-modal)
  • In some cases, the distribution may have no mode at all
  • Mode may not be suitable if all values are different
• Find the mode


  Simply find the most recurring value