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Chapter 16: One-Way Analysis of Variance
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Note:
The length of the box in a box plot represents the interquartile range. Thus,
in a horizontal box plot, the left edge of the box represents the first quartile
or the 25
th
percentile. Equivalently, the right edge of the box represents the
third quartile or the 75
th
percentile.
We can use the information given in the previous note to also use a different
rule of thumb to help determine whether one may conclude whether the
population averages are significantly different.
Rule of Thumb
:
This rule of thumb states that if the first quartile
(25
th
percentile) for any of the box plots is greater than the median of any of
the other box plots, then one may infer that the respective population means
may be significantly different.
Applying this rule we may make the same inference on the population
means as the previous rule of thumb.