Mathdemo

• Measures of central tendency (mean, median, mode) are used to describe a set of data
• The mean for an ungrouped data is the sum of the values in the set divided by the number of values added
• Mean


  A value that indicates the center of a set of data when the data are arranged in increasing or decreasing order
• The median is the middle value of a set of data when the values are arranged in ascending or descending order
• Median


  The middle value, with half the values above and half below
• If there is an odd number of values, the median is the middle value. If there is an even number of values, the median is the mean of the two middle values.
• Mode


  The value that occurs most frequently in a data set
• Types of mode


  • Unimodal (one mode)
  • Bimodal (two modes)
  • Multimodal (more than two modes)
• If no value occurs more than once, the data does not have a mode
• Finding mean, median, and mode

  1. Arrange data in ascending/descending order

  2. For mean, sum values and divide by number of values

  3. For median, find middle value or average of two middle values

  4. For mode, identify most frequent value
• Example 1


  • 43, 37, 30, 35, 41, 23, 31, 33, 16, 37
  • Mean = 32.6
  • Median = 34
  • Mode = 37 (unimodal)
• Example 2


  • 90, 50, 70, 80, 70, 20, 60, 80, 20