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Chapter 4: Measures of Position
169
Example 4-9:
The average lifespan of a peasant during the middle ages
was 25 years. Below are the life spans of 12 peasants. Determine if the
lifespan of 43 years is an outlier.
15 20 25 30 17 43 22 29 15 17 18 19
Solution:
First, we need to arrange the data set in order. The ordered set is
given below.
15 15 17 17 18 19 20 22 25 29 30 43
Next we need to determine the first and third quartiles and the interquartile
range. Using the
Basic Statistics
workbook, we can verify that
=
=
17,
=
= 27, and the
= 10.
Now,
– 1.5
= 17 – (1.5
10) = 2 and,
+ 1.5
= 27 + (1.5
10)
= 42. Since, 43 > 42, the value of 43 is an outlier relative to the rest of the
values in the data set (based on the
Inner Fence Test
). Refer to
Figure 4-20
for the computations.
Figure 4-20:
Results for the Inner Fence Test for
Example 4-9
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