Part II: Working with Formulas and Functions
FIGURE 16.14
Sorted data and demarcation lines
To identify outliers, we’ll use a method called a leveraged interquartile range. An interquar-
tile range is simply the data that lies in the middle 50% (between the 75th percentile and
the 25th percentile). The “leveraged” part means that we expand that middle range by a
factor and establish fences. Any data outside the fence is considered an outlier.
The formulas used in Figure 16.15 are shown here:
75th percentile: =QUARTILE.EXC($C$3:$C$22,3)
25th percentile: =QUARTILE.EXC($C$3:$C$22,1)
Interquartile Range: =G4-G5
