priyan

• Mean


  The most commonly used measure of central position, calculated as the sum of measures x divided by the number N of measures
• Median


  The middle value when the data is arranged in order from smallest to largest
• Mode


  The value that occurs most frequently in the data set
• Finding the mean of ungrouped data


  Σx/N
• The mean is symbolized as X̅ (read as "X-bar")
• The median is the middle value when the data is arranged in order from smallest to largest
• The mode is the value that occurs most frequently in the data set
• Measures of central tendency


  Any measure indicating the center of a set of data
• Three kinds of averages

  • Mean
  • Median
  • Mode
• Mean


  The most commonly used measure of central position, calculated as the sum of measures divided by the number of measures
• Finding the mean


  Σx/N
• Median


  The middle value in a set of data, found by arranging the values in order
• Finding the median


  Arrange the values in order, find the middle value (or average of the two middle values if even number of values)
• Mode


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


  Select the measure that appears most often

  2. If two or more measures appear the same number of times, each is a mode

  3. If every measure appears the same number of times, there is no mode
• Measures of central tendency are mean, median and mode
• The mean is also referred to as an average
• The median is the middle value in a set of data
• The mode is the value that appears most frequently
• If two or more values appear the same number of times, they are all modes
• If every value appears the same number of times, there is no mode
• Median


  The middle value when the quantities are arranged according to magnitude (from highest to lowest)
• Computing for the median of grouped data

  Median = 𝑙𝑏𝑚𝑐+ [

  ∑𝑓

  2 −<𝑐𝑓

  𝑓𝑚�� ] 𝑖
• 𝑙𝑏𝑚𝑐


  Lower boundary of the median class
• ��


  Frequency of each class
• <𝑐𝑓


  Cumulative frequency of the lower class next to the median class
• ��


  Class interval
• The median class is the class with the smallest cumulative frequency greater than or equal to

  ∑𝑓

  2 . The computed median must be within the median class.
• 4th Periodical Test Scores of Grade 7-Narnia Students in Mathematics

  • 46-50
  • 41-45
  • 36-40
  • 31-35
  • 26-30
• Frequency


  • 2
  • 2
  • 5
  • 7
  • 4
• Lower Class Boundary


  • 45.5
  • 40.5
  • 35.5
  • 30.5
  • 25.5
• Less than Cumulative Frequency

  • 20
  • 18
  • 16
  • 11
  • 4
• 𝑖 = 5, ∑𝑓 = 20
• Calculating the median


  Median = 𝑙𝑏𝑚𝑐+ [

  ∑𝑓

  2 −<𝑐𝑓

  𝑓𝑚𝑐 ] 𝑖
• ∑𝑓

  2 = 20

  2 =10
• The 10th score is contained in the class 31-35. This means that the median falls within the class boundaries of 31-35, which is 30.5-35.5
• <𝑐𝑓 = 4
• 𝑓𝑚𝑐 = 7
• 𝑙𝑏 = 30.5
• 𝑖 = 5