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Median

(Last edited: Tuesday, 14 March 2017, 8:55 AM)
  • Value of the observation that falls in the middle when observations are ranked in order
  • Formula: 
  1. Uneven number of observations: Median= x(n+1)/2
  2. Even number of observations: Median= (x(n/2)+ x(n+2)/2)/ 2
  • Example: 

Order all observations from smallest to highest number

  1. Uneven number of observations: n= 7 
Set of numbers (ordered from smallest to biggest number): 3, 4, 5, 5, 5, 6, 7 
Median: x(n+1)/2 = x(7+1)/2= x4→ x4= 5
 
2. Even number of observations: n= 8

Set of numbers (ordered from lowest to highest number): 3, 4, 5, 5, 6, 6, 7, 9

Median: (x(n/2)+ x(n+2)/2)/ 2= (x(8/2)+ x(8+2)/2)/ 2= (x4+ x5)/ 2= (5+ 6)/ 2= 11/ 2= 5.5

 

 

 

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