Univariate Graphs III

• Review

• Create histogram from Commands Window.

• Multipanel histogram.

• Quantile Plots

• Quantile-Normal Plots

• Quantile-Quantile Plots

Histogram from Commands

• From the Command Window typegraphsheet(height=6.4,width=7.5)hist(iris$sepal.length, nclass=10, xlab="sepal.length")

• Graphs from the Commands Window are fixed unless…

• Right click on the histogram and select Convert to Objects.

• Now you can change the axis scales, etc.

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sepal.length

Multipanel Histogram

• In the Iris data window, select sepal.length and then CTRL select variety.

• Using the Graph->Multipanel menu, plot a Histogram.

• Note that under Conditioning Columns, the column list is variety

• Try changing the number of rows and columns in the layout to be 2 by 2

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sepal.length

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Virginica

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sepal.length

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Virginica

Multipanel Histogram for Several Variables

• In the Iris data window, select sepal.width and then CTRL select variety.

• Using the Graph->Multipanel menu, plot a Histogram.

• Select the same Graphsheet as was used for the previous histogram

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01020

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Setosa

Versicolor

Virginica

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Versicolor

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Versicolor

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Versicolor

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Setosa Versicolor

Virginica

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Quantile Plots

• A Quantile Plot graphs the value of each observation against the fraction of observations that are equal to or less than that observation

where i is the index of the observation in a sorted list from i = 1 to N

N

ifi

5.0−=

Quantile Plot of Sepal Length

graphsheet(height=6.4,width=6.4)

tLength <- length(iris$sepal.length)

plot(c(1:tLength)/tLength,

sort(iris$sepal.length),

xlab = "Fraction Value",

ylab="Sepal Length (cm)")

Quantile Plot of Sepal Length

graphsheet(height=6.4,width=6.4)

qqmath(~ sepal.length,

distribution=qunif, data=iris,

aspect=1,

xlab = "Fraction Value",

ylab="Sepal Length (cm)")

Quantile Plot of Sepal Length

graphsheet(height=4,width=7.5)

qqmath(~ sepal.length | variety,

distribution=qunif, data=iris,

panel = function(x, y) {

panel.grid()

panel.xyplot(x, y)

},

layout=c(3,1), aspect=1,

xlab = "Fraction Value",

ylab="Sepal Length (cm)")

Quantile-Normal PlotUsing Menus

• In the Iris data window, select sepal.length.

• Using the Graph->2D menu, select a Q-Q Plot.

• Right click on the graph, select Position/Size and then set the Aspect Ratio to 1.

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Normal Distribution

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sepal.length

Quantile-Normal Plot

graphsheet(height=6.4,width=6.4)

qqnorm(iris$sepal.length, xlab = "Quantiles from Normal Distribution",

ylab = "Quantiles from Sample")

Quantile-Normal Trellis Plot

graphsheet(height=6.4,width=6.4)

qqmath(~ sepal.length,

distribution=qnorm, data=iris,

prepanel = prepanel.qqmathline,

panel = function(x, y) {

panel.qqmathline(y, distribution = qnorm)

panel.qqmath(x, y)

},

aspect=1,

xlab = "Normal Distribution",

ylab="Sepal Length (cm)")

Quantile-Normal Trellis Plot

graphsheet(height=6.4,width=6.4)

qqmath(~ sepal.length | variety,

distribution=qnorm, data=iris,

prepanel = prepanel.qqmathline,

panel = function(x, y) {

panel.qqmathline(y, distribution = qnorm)

panel.qqmath(x, y)

},

aspect=1, layout=c(2,2),

xlab = "Normal Distribution",

ylab="Sepal Length (cm)")

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Setosa

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Versicolor

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Virginica

Normal Distribution

Sepal Length (cm)

Quantile-Quantile PlotUsing Menus

• In the Iris data window, select sepal.length.

• CTRL select petal.length

• Using the Graph->2D menu, select a Q-Q Plot.

• Right click on the graph, select Position/Size and then set the Aspect Ratio to 1.

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sepal.length

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Quantile-Quantile Trellis Plot

graphsheet(height=6.4,width=6.4)

qq(variety ~ sepal.length, data=iris,subset = variety=="Setosa" | variety=="Versicolor",aspect=1)

For Thursday

• Read A Tour of Trellis Graphics pp 1-17 (download from the following web page)http://cm.bell-labs.com/cm/ms/departments/sia/project/trellis/software.writing.html

• Reaction papers are due October 3rd.