math

• measure of central tendency


  a summary measure that attempts to describe a whole set of data with a single value that represents the middle or center of its distribution
• mean


  the sum of the value of each observation in a dataset divided by the number of observation
• mean


  also known as the arithmetic average
• median


  the middle value in distribution when the values are arranged in ascending or descending order
• the median divides the distribution in half
• mode


  the most commonly occuring value in a distribution
• steps in interpolation

  1. locate the position on the given data
  2. subtract the 3rd value to the 2nd value
  3. multiply the result by the decimal part on the position and into the obtained value on step 2
  4. add the result in step 3 to the smallest value used in step 1
• quartile


  the score points which divided a distribution into four equal parts
• formula of lower quartile

  Q1 = 1/4 (n+1)
• formula of upper quartile

  Q3 = 3/4 (n+1)
• decile


  are the nine score points which divides a distribution into ten equal parts.
• formula of decile (ungrouped)

  Dk = k/10 (n+1)
• percentile


  are the ninety-nine score points which divide a distribution into one hundred equal parts, so that each part represents the data set.
• formula of percentile (ungrouped)

  Pk = k/100 (n+1)
• the difference between Q3 and Q1 is the Interquartile Range
• formula of quartile (grouped data)

  Qk= LB + (kN/4 - Cfb over Fqk) i
• formula of decile (grouped data)

  Dk= LB + (kN/10 - Cfb over Fdk) i
• formula of percentile (grouped data)

  Pk= LB + (kN/100 - Cfb over Fpk) i
• Grouped Data

  LB = Lower Boundery

  N= total frequency

  Cfb= cumulative frequency of the class before the Qk class

  F= frequency of the Qk class

  i= size of class interval

  k= nth quartile, where n= 1, 2 and 3
• population mean

  u (pronounced 'mu')
• sample mean

  x - (pronounced x-bar)