plot::Boxplot

Statistical box plots

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Syntax

plot::Boxplot(L1, …, <a = amin .. amax>, options)
plot::Boxplot([L1, …], <a = amin .. amax>, options)
plot::Boxplot(A, <a = amin .. amax>, options)
plot::Boxplot(s, <c1, …>, <a = amin .. amax>, options)
plot::Boxplot(s, <[c1, …]>, <a = amin .. amax>, options)

Description

plot::Boxplot(data) creates a box plot of the given data.

plot::Boxplot creates a box plot of discrete data samples. Box plots reduce data samples to a number of descriptive parameters and are a useful means of comparing statistical data.

In particular, each data sample is represented as one box. A typical box consists of the following subparts:

  • A “central box” representing the central 50% of the data. Its lower and upper boundary lines are at the 25%/75% quantile of the data. A central line indicates the median of the data.

  • Two vertical lines extending from the central box indicating the remaining data outside the central box that are not regarded as outliers. These lines extend maximally to times the height of the central box but not past the range of the data.

  • Outliers: these are points indicating the remaining data.

With the special attribute Notched = TRUE, the sides of the boxes can be notched, thus providing additional information on the data sample. The horizontal width of the notches may be set by the attribute NotchWidth.

The special attributes BoxCenters and BoxWidths allow to center the boxes at arbitrary positions along the horizontal axis and to set the horizontal width of the boxes, respectively.

The special attribute Averaged determines whether the quantile values are computed with or without the option Averaged (cf. stats::empiricalQuantile).

Specifying DrawMode = Horizontal, the boxes are rotated by 90 degrees.

The attribute Colors allows to specify the color of each box in a box plot. A common color for all boxes may be specified via Color.

Attributes

AttributePurposeDefault Value
AffectViewingBoxinfluence of objects on the ViewingBox of a sceneTRUE
AntiAliasedantialiased lines and points?FALSE
Averagedmode for computing quantile lines in box plotsTRUE
BoxWidthswidths of boxes in a box plot[0.8]
BoxCentersposition of boxes in a box plot[1]
Colorthe main color 
Colorslist of colors to use[RGB::Blue, RGB::Red, RGB::Green, RGB::MuPADGold, RGB::Orange, RGB::Cyan, RGB::Magenta, RGB::LimeGreen, RGB::CadmiumYellowLight, RGB::AlizarinCrimson]
Datathe (statistical) data to plot 
DrawModeorientation of boxes and barsVertical
Filledfilled or transparent areas and surfacesTRUE
FillPatterntype of area fillingDiagonalLines
Framesthe number of frames in an animation50
Legendmakes a legend entry 
LegendTextshort explanatory text for legend 
LegendEntryadd this object to the legend?FALSE
LineWidthwidth of lines0.35
LineStylesolid, dashed or dotted lines?Solid
LinesVisiblevisibility of linesTRUE
Namethe name of a plot object (for browser and legend) 
Notchednotched boxes in box plotsFALSE
NotchWidthwidth of notches in box plots0.2
ParameterEndend value of the animation parameter 
ParameterNamename of the animation parameter 
ParameterBegininitial value of the animation parameter 
ParameterRangerange of the animation parameter 
TimeEndend time of the animation10.0
TimeBeginstart time of the animation0.0
TimeRangethe real time span of an animation0.0 .. 10.0
Titleobject title 
TitleFontfont of object titles[" sans-serif ", 11]
TitlePositionposition of object titles 
TitleAlignmenthorizontal alignment of titles w.r.t. their coordinatesCenter
TitlePositionXposition of object titles, x component 
TitlePositionYposition of object titles, y component 
VisiblevisibilityTRUE
VisibleAfterobject visible after this time value 
VisibleBeforeobject visible until this time value 
VisibleFromToobject visible during this time range 
VisibleAfterEndobject visible after its animation time ended?TRUE
VisibleBeforeBeginobject visible before its animation time starts?TRUE

Examples

Example 1

Just to show basic usage of plot::Boxplot, we plot some data samples chosen arbitrarily:

data1 := [5, 10, 24, -4, 13]:
data2 := [7, 9, -1, 4, 10, 8, 12, 10, 15]:
b := plot::Boxplot(data1, data2):
plot(b)

We can modify the appearance of the box plot in various ways:

b::Notched := TRUE:
b::Colors  := [RGB::Green, RGB::Black]:
b::BoxCenters := [2, 3]:
b::FillPattern := XCrossedLines:
plot(b)

delete b:

Example 2

It is possible to shift the whole plot in x-direction by providing a center for the first box via BoxCenters:

A := matrix([[ 5,  6,  19], 
             [10,  5,  45], 
             [24,  2,  12],
             [-3, 18, -10],
             [-4,  0, - 4]]):
plot(plot::Boxplot(A, BoxCenters = [2], Notched = TRUE, 
                   FillPattern = Solid))

delete A:

Example 3

The primary use of plot::Boxplot is comparing data sets. We shall do this for data produced by the following random number generators:

f := stats::normalRandom(1, 0.2):
g := stats::uniformRandom(0, 2):

Now, we create small samples and compare their boxes:

data1 := [f() $ k = 1..100]: // Red
data2 := [f() $ k = 1..100]: // Green
data3 := [g() $ k = 1..100]: // Blue
plot(plot::Boxplot(data1, data2, data1, data3, data2, data3,
     Colors = [RGB::Red, RGB::Green, RGB::Red, RGB::Blue,
               RGB::Green, RGB::Blue], 
     BoxCenters = [1, 2, 4, 5, 7, 8], Notched = TRUE))

Comparing the central boxes, the blue data differ significantly from the red and the green data. The red and green boxes, however, are quite similar – as they should, given that the red and green data were produced by the same random generator f.

delete f, g, data1, data2, data3:

Example 4

For symmetric input data, the images generated by plot::Boxplot are symmetric, too:

plot(plot::Boxplot([$0..10], [5+5*sin(PI*n/20) $ n=-10..10], Notched))

Example 5

By default, the quantile lines of the boxes are computed with the option Averaged (see stats::empiricalQuantile for details). When using Averaged = FALSE, the quantiles are computed without this option:

r := random(0..10):
SEED := 123:
data := [r() $ k = 1..250]:
plot(plot::Boxplot(data, Averaged = TRUE, BoxCenters = 0.5,
                         Color = RGB::Blue, Notched),
     plot::Boxplot(data, Averaged = FALSE, BoxCenters = 1.5,
                         Color = RGB::Red, Notched)
    ):

delete r, SEED, data:

Example 6

Box plots can be animated. We create two data samples and fuse them to a symbolic superposition:

f1 := stats::normalRandom(0, 1):
f2 := stats::normalRandom(4, 8):
data0 := sort([f1() $ k = 1..100]):
data1 := sort([f2() $ k = 1..100]):
data01 := [(1 - a)*data0[i] + a*data1[i] $ i = 1..100]:

The box associated with the data sample data01 changes from the box associated with data0 to the box associated with data1 as the animation parameter increases from a = 0 to a = 1:

plot(plot::Boxplot(data0, data01, data1, a = 0..1))

delete f1, f2, data0, data1, data01:

Parameters

L1, …

Data samples: lists of numerical real values or arithmetical expressions of the animation parameter a.

L1, … is equivalent to the attribute Data.

A

An array of domain type DOM_ARRAY or a matrix of category Cat::Matrix (e.g., of type matrix or densematrix) providing numerical real values or arithmetical expressions of the animation parameter a. The columns are regarded as separate data samples. Also a 1-dimensional array, regarded as a single data sample, is accepted.

A is equivalent to the attribute Data.

s

A data collection of domain type stats::sample. The columns in s are regarded as separate data samples.

s is equivalent to the attribute Data.

c1, …

Column indices into s: positive integers. These indices, if given, indicate that only the specified columns in s should be used as data samples. If no column indices are specified, all columns in s are used as data samples.

a

Animation parameter, specified as a = amin..amax, where amin is the initial parameter value, and amax is the final parameter value.

See Also

MuPAD Functions

MuPAD Graphical Primitives