Page 29 - Basic Statistics

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2.2 DISPERSION OF DATA

Known to some measure of the dispersion of the data, such as:

a. Range and modified Ranges

b. The average deviation

c. Standard deviation

d. Variance
e. Coefficient of variation

but only some of this measure of the dispersion are discussed in this book.

2.2.1 DISPERSION OF UNGROUP DATA

a. Range

Range of a set of data states that width of the data. For data of a sampling
result, the range is calculated from the difference between the maximum value

(Xmax) with a minimum value (Xmin).

In an ordered data set : Xmin , X2 , X3 , …, Xmax.

Range ; Rg = Xmax - Xmin

b. Modified Ranges

Modified range based on various measures of the partitioning a set of

ordered data, according to some of the same parts. The partitioning of data into
several parts, can be the quartiles ( 4 parts), the deciles (10 parts), and the

percentiles (100 parts).

Quartiles measure are defined as follows

1. First quartile (Q1) is the observation value that lies at the location to ((n

+1) / 4)th in the ordered data. Partitioning the data on 25% down and
75% up.

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