These points are extreme, quite a long way from the rest of the data. They have been separated from the rest of the data. The usual convention is that points are regarded as `outside' if they are further than 1.5 times the interquartile range from the quartile, i.e. from the edge of the box. Such points are sometimes shown separately from the whiskers, as here, sometimes included within the whisker (Intro 4.3).
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Last updated: 8 April, 2004.