Page 25 - Basic Statistics

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b. Median

The median of a set of data is the middle value when the data are

arranged from the smallest value to the largest valuein an array. Once the data

is sorted, the median is defined as :

Med = The value of ((n + 1 ) / 2)th observations
Med = X (n + 1 ) / 2

Where,

Med = Median
n = Number of observations

Median for odd-sized data can be directly identified, because the median

is listed on the data. If the data size is even then the median is the average of the

two middle observations in the ordered data.

Worked Example 2.2 :

Determine the median of the following data

a. 8, 4, 4, 3, 5, 9, 10, 8, 8, 7, 9
b. 5, 5, 4, 7, 8, 9, 8, 10, 10, 3, 4, 10

Worked Solution :

a. Ordered data : 3, 4, 4, 5, 7, 8, 8, 8, 9, 9, 10

Med = the value of the data in the ((11 +1) / 2)th observation

= the value of the data in the 6th observation

Med = X6

= 8

~~* CHAPTER 2 NUMERICAL MEASURES TO SUMMARIZE DATA *~~