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Chapter 4: Measures of Position
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Figure 4-13:
Computed percentile for
Example 4-7
Next we will discuss some special percentiles.
Special Percentiles – Deciles and Quartiles
Here we will introduce some special groups of percentiles. Two special
groups of percentiles are
deciles
and
quartiles
. Deciles divide an ordered
data set into 10 equal parts while quartiles divide it into four equal parts.
We usually denote the deciles by
,
, …,
, and quartiles by
,
,
and
. Note, based on the notations, that there are nine deciles and there
are three quartiles. The deciles are depicted in
Figure 4-14.
In the case of
the deciles, there are at most 10 percent of the values within each group.
Figure 4-14:
Pictorial representation of Deciles
The quartiles are depicted in
Figure 4-15
, In the case of quartiles, there are
at most 25 percent of the values within each group.
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