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A simple more general boxplot method for identifying outliers

Schwertman, Neil C. and Owens, Margaret Ann and Adnan, Robiah (2004) A simple more general boxplot method for identifying outliers. Computational Statistics and Data Analysis , 47 . pp. 165-174. ISSN 01679473

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Official URL: http://dx.doi.org/10.1016/j.csda.2003.10.012


The boxplot method (Exploratory Data Analysis, Addison-Wesley, Reading, MA, 1977) is a graphically-based method of identifying outliers which is appealing not only in its simplicity but also because it does not use the extreme potential outliers in computing a measure of dispersion. The inner and outer fences are defined in terms of the hinges (or fourths), and therefore are not distorted by a few extreme values. Such distortion could lead to failing to detect some outliers, a problem known as "masking". A method for determining the probability associated with any fence or observation is proposed based on the cumulative distribution function of the order statistics. This allows the statistician to easily assess, in a probability sense, the degree to which an observation is dissimilar to the majority of the observations. In addition, an adaptation for approximately normal but somewhat asymmetric distributions is suggested.

Item Type:Article
Uncontrolled Keywords:approximation theory, graph theory, probability, set theory, statistical methods, boxplot method, outliers, quartiles, data reduction
Subjects:Q Science > QA Mathematics > QA76 Computer software
ID Code:12180
Deposited By: Liza Porijo
Deposited On:23 Mar 2011 00:29
Last Modified:08 Oct 2017 04:54

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