InterquartileRange

Package

weka.filters.unsupervised.attribute

A filter for detecting outliers and extreme values based on interquartile ranges. The filter skips the class attribute.

Outliers:
Q3 + OF*IQR < x <= Q3 + EVF*IQR
or
Q1 - EVF*IQR <= x < Q1 - OF*IQR

Extreme values:
x > Q3 + EVF*IQR
or
x < Q1 - EVF*IQR

Key:
Q1 = 25% quartile
Q3 = 75% quartile
IQR = Interquartile Range, difference between Q1 and Q3
OF = Outlier Factor
EVF = Extreme Value Factor

The table below describes the options available for InterquartileRange.

Option	Description
attributeIndices	Specify range of attributes to act on; this is a comma separated list of attribute indices, with "first" and "last" valid values; specify an inclusive range with "-", eg: "first-3,5,6-10,last".
debug	Turns on output of debugging information.
detectionPerAttribute	Generates Outlier/ExtremeValue attribute pair for each numeric attribute, not just a single pair for all numeric attributes together.
extremeValuesAsOutliers	Whether to tag extreme values also as outliers.
extremeValuesFactor	The factor for determining the thresholds for extreme values.
outlierFactor	The factor for determining the thresholds for outliers.
outputOffsetMultiplier	Generates an additional attribute 'Offset' that contains the multiplier the value is off the median: value = median + 'multiplier' * IQR

The table below describes the capabilites of InterquartileRange.

Capability	Supported
Class	Unary class, Relational class, Date class, Missing class values, Numeric class, No class, String class, Empty nominal class, Binary class, Nominal class
Attributes	Missing values, Nominal attributes, String attributes, Empty nominal attributes, Relational attributes, Binary attributes, Date attributes, Unary attributes, Numeric attributes
Min # of instances	0