Statistical Analysis Stack Exchange
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Questions tagged [boxplot]

A graphical display to summarize the distribution of a sample. It displays five numbers plus (possibly) some outliers - those five points being the median, hinges (approximate quartiles), and the largest and smallest value not counting any points marked as outliers.

A boxplot or box-and-whisker plot is a graphical display that summarizes a sample distribution. Mostly used when comparing many samples, it displays five numbers plus (possibly) some outliers. The five numbers are the median (drawn as a central line) and hinges - approximate quartiles - for which a box is drawn. Then lines are drawn out to the largest and smallest values not marked as outliers. There are many variants of the basic boxplot.

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Is there a boxplot variant for Poisson distributed data?

I'd like to know if there is a boxplot variant adapted to Poisson distributed data (or possibly other distributions)? With a Gaussian distribution, whiskers placed at L = Q1 - 1.5 IQR and U = Q3 + 1.5 IQR, the boxplot has the property that there…
caas
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What are good data visualization techniques to compare distributions?

I am writing my PhD thesis and I've realized that I rely excessively in box plots in order to compare distributions. Which other alternatives do you like for achieving this task? I'd also like to ask if you know any other resource as the R gallery…
pedrosaurio
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How to present box plot with an extreme outlier?

I could use some guidance about presenting some data. This first plot is a case-control comparison for the cytokine IL-10. I've manually set the y axis to include 99% of the data. The reason I set this manually is because the case group has an…
Alex C
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What are some alternatives to a boxplot?

I am working on creating a website, which displays the census data for a user selected Polygons & would like to graphically show the distribution of various parameters (one graph per parameter). The data usually has the following properties: The…
Devdatta Tengshe
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How to assess skewness from a boxplot?

How to decide skewness by looking at a boxplot built from this data: 340, 300, 520, 340, 320, 290, 260, 330 One book says, "If the lower quartile is farther from the median than the upper quartile, then the distribution is negatively skewed."…
JerryW
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What's the history of box plots, and how did the "box and whiskers" design evolve?

Many sources date the classic "box plot" design to John Tukey and his "schematic plot" of 1970. The design seems to have stayed relatively static since then, with Edward Tufte's cut-down version of the box plot failing to catch on, while violin…
Silverfish
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What is the basis for the Box and Whisker Plot definition of an outlier?

The standard definition of an outlier for a Box and Whisker plot is points outside of the range $\left\{Q1-1.5IQR,Q3+1.5IQR\right\}$, where $IQR= Q3-Q1$ and $Q1$ is the first quartile and $Q3$ is the third quartile of the data. What is the basis for…
Tavrock
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"When to use boxplot and when barplot" rules (of thumb?)

Both box-and-whisker plot and bar chart are appropriate graphics for ANOVA according to The R Book (Crawley, 2013), but which is more appropriate? I suppose it depends on situation... can anybody help me?
Ladislav Naďo
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Show average instead of median in boxplot

When plotting a boxplot with python matplotblib, the lines halfway the plot is the median of the distribution. Is there a possibility to instead have the line at the average. Or to plot it next to it in a different style. Also, because it is common…
Peter Smit
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What information does a Box Plot provide that a Histogram does not?

Histograms give a good sense of the distribution of a variable. Box plots attempt to do the same thing however, don't give as good of a picture of the distribution of this variable. I don't understand why people use box plots. Histograms are better…
user46925
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Deduce variance from boxplot

I was wondering how to deduce the variance of a variable using a boxplot. Is it at least possible to deduce if two variables have the same variance observing their boxplot?
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Visualizing many left-skewed distributions

I have a series of left-skewed/heavy tailed distributions that I would like to show. There are 42 distributions across three factors (labeled as A, B and C below). Also, the variation is shrinking across factor B. The issue I have is that the…
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What is a 'bagplot', or 'bivariate boxplot'?

I've found a paper which introduces the multidimensional (bivariate here) version of the boxplot - a bagplot. What is that bagplot exactly? I can see the series of nested polygons based on vertices, one of those polygons being declared as a bagplot.…
mbaitoff
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Why is the 95% CI for the median supposed to be $±1.57*IQR/\sqrt{N}$?

In various sources (see e.g. here), the following formula is given for confidence interval for median (especially for the purpose of drawing notches on box-and-whisker plots): $$ 95\%\ CI_{\rm median} = {\rm Median} \pm \frac{1.57\times…
Ilya V. Schurov
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What kind of chart is this?

Sorry for the vague question but this chart appears in Biddle et al. 2009 and I've not encountered anything like it before. It's a bar chart with beveled edges, sometimes 'horns'. What do these mean? Does this type of chart have a name? Per…
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