Box_plot - Box plot - Wikipedia, the free encyclopedia Page...

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Box plot From Wikipedia, the free encyclopedia In descriptive statistics, a box plot or boxplot (also known as a box-and-whisker diagram or plot ) is a convenient way of graphically depicting groups of numerical data through their five- number summaries: the smallest observation (sample minimum), lower quartile (Q1), median (Q2), upper quartile (Q3), and largest observation (sample maximum). A boxplot may also indicate which observations, if any, might be considered outliers. Boxplots can be useful to display differences between populations without making any assumptions of the underlying statistical distribution: they are non-parametric. The spacings between the different parts of the box help indicate the degree of dispersion (spread) and skewness in the data, and identify outliers. Boxplots can be drawn either horizontally or vertically. Alternative forms Box and whisker plots are uniform in their use of the box: the bottom and top of the box are always the 25 th and 75 th percentile (the lower and upper quartiles, respectively), and the band near the middle of the box is always the 50 th percentile (the median). But the ends of the whiskers can represent several possible alternative values, among them: ± the minimum and maximum of all the data [1] ± the lowest datum still within 1.5 IQR of the lower quartile, and the highest datum still within 1.5 IQR of the upper
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This note was uploaded on 05/05/2010 for the course STAT 601 taught by Professor Wherly during the Spring '08 term at Texas A&M.

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Box_plot - Box plot - Wikipedia, the free encyclopedia Page...

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