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Activity Number:
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198
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Type:
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Contributed
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Date/Time:
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Monday, August 7, 2006 : 2:00 PM to 3:50 PM
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Sponsor:
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Section on Statistical Graphics
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| Abstract - #306759 |
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Title:
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Letter Value Box Plots: Box Plots for Large Datasets
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Author(s):
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Karen Kafadar*+ and Heike Hofmann and Hadley Wickham
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Companies:
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University of Colorado and Iowa State University and Iowa State University
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Address:
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Department of Mathematics, Denver, CO, 80217-3364,
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Keywords:
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boxplot ; distribution ; shape
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Abstract:
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Conventional boxplots are useful displays for conveying rough information about the data distributional shape. Tail information beyond the quartiles (whiskers) can be unreliable in small samples so whiskers show only the extent of the outer quartiles. Thus, boxplots present two shortcomings for large data sets: more "outliers" are labeled and information about tail behavior is sparse. Letter value box plots address both shortcomings: a fixed, reasonably small, number of outliers can be labeled, and more detailed estimates of tail behavior based on letter values beyond the quartiles can be shown. We describe their construction and illustrate their usefulness on real data sets.
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