Plot the results of calling the function gofTest to compare
two samples. gofTest returns an object of class "gofTwoSample"
when supplied with both the arguments y and x.
plot.gofTwoSample provides five different kinds of plots.
The function plot.gofTwoSample is automatically called by plot
when given an object of class "gofTwoSample". The names of other functions
associated with goodness-of-fit test are listed under Goodness-of-Fit Tests.
# S3 method for gofTwoSample
plot(x, plot.type = "Summary",
captions = list(PDFs = NULL, CDFs = NULL, QQ = NULL, MDQQ = NULL, Results = NULL),
x.labels = list(PDFs = NULL, CDFs = NULL, QQ = NULL, MDQQ = NULL),
y.labels = list(PDFs = NULL, CDFs = NULL, QQ = NULL, MDQQ = NULL),
same.window = FALSE, ask = same.window & plot.type == "All", x.points.col = "blue",
y.points.col = "black", points.pch = 1, jitter.points = TRUE, discrete = FALSE,
plot.pos.con = 0.375, x.ecdf.col = "blue", y.ecdf.col = "black",
x.ecdf.lwd = 3 * par("cex"), y.ecdf.lwd = 3 * par("cex"), x.ecdf.lty = 1,
y.ecdf.lty = 4, add.line = TRUE,
digits = ifelse(plot.type == "Summary", 2, .Options$digits), test.result.font = 1,
test.result.cex = ifelse(plot.type == "Summary", 0.9, 1) * par("cex"),
test.result.mar = c(0, 0, 3, 0) + 0.1,
cex.main = ifelse(plot.type == "Summary", 1.2, 1.5) * par("cex"),
cex.axis = ifelse(plot.type == "Summary", 0.9, 1) * par("cex"),
cex.lab = ifelse(plot.type == "Summary", 0.9, 1) * par("cex"),
main = NULL, xlab = NULL, ylab = NULL, xlim = NULL, ylim = NULL,
add.om.title = TRUE,
oma = if (plot.type == "Summary" & add.om.title) c(0, 0, 4, 0) else c(0, 0, 0, 0),
om.title = NULL, om.font = 2, om.cex.main = 1.5 * par("cex"), om.line = 0, ...)an object of class "gof". See gof.object for details.
character string indicating what kind of plot to create. Only one particular
plot type will be created, unless plot.type="All", in which case all plots
will be created sequentially. The possible values of plot.type are:
"Summary" (the default),
"PDFs: Observed",
"CDFs: Observed",
"Q-Q Plot",
"Tukey M-D Q-Q Plot",
"Test Results", and
"All".
See the DETAILS section for more information.
a list with 1 to 5 components with the names "PDFs", "CDFs",
"QQ", "MDQQ", and/or "Results". Each component either has
the value NULL or else it is a character string containing the title for that
particular kind of plot. When the component has the value NULL (the default),
a default title is used. This argument is useful when you are creating more than
one kind of plot with a single call to plot.gofTwoSample (i.e., when
plot.type="Summary" or plot.type="All") and you want to specify titles
different from the default ones. If you are creating only one kind of plot,
then you can just use the main argument to specify a title different
from the default one.
a list of 1 to 4 components with the names "PDFs", "CDFs", "QQ",
and/or "MDQQ". Each component either has the value
NULL or else it is a character string containing the label for the
\(x\)-axis for that particular kind of plot. When the component has the value
NULL (the default), a default \(x\)-axis label is used.
This argument is useful when you are creating more than
one kind of plot with a single call to plot.gofTwoSample (i.e., when
plot.type="Summary" or plot.type="All")
and you want to specify \(x\)-axis
labels different from the default ones. If you are creating only one plot,
then you can just use the xlab argument to
specify an \(x\)-axis label different from the default one.
a list of 1 to 4 components with the names "PDFs", "CDFs", "QQ",
and/or "MDQQ". Each component either has the value
NULL or else it is a character string containing the label for the
\(y\)-axis for that particular kind of plot. When the component has the value
NULL (the default), a default \(y\)-axis label is used.
This argument is useful when you are creating more than
one kind of plot with a single call to plot.gofTwoSample (i.e., when
plot.type="Summary" or plot.type="All")
and you want to specify \(y\)-axis
labels different from the default ones. If you are creating only one plot,
then you can just use the ylab argument to
specify a \(y\)-axis label different from the default one.
logical scalar indicating whether to produce all plots in the same graphics
window (same.window=TRUE), or to create a new graphics
window for each separate plot (same.window=FALSE; the default).
The argument is relevant only when plot.type="All".
logical scalar supplied to the function devAskNewPage, indicating
whether to prompt the user before creating a new plot within a single graphics
window. The default value is FALSE unless same.window=TRUE and
plot.type == "All".
logical scalar indicating whether to jitter the points in the strip chart.
The default value is jitter.points=TRUE.
logical scalar indicating whether the two distributions are considered to be
discrete (discrete=TRUE) or not(discrete=FALSE; the default). When
discrete=TRUE, the empirical CDFs are plotted as step functions.
numeric scalar between 0 and 1 containing the value of the plotting position
constant used to construct the observed (empirical) CDFs. The default value
is plot.pos.con=0.375. See the help files for
ecdfPlot and qqPlot for more information and the
motivation for this choice of values.
NOTE: This argument is also used to determine the value of the
plotting position constant for the Q-Q plot (plot.type="Q-Q Plot"), or the
Tukey Mean-Difference Q-Q plot (plot.type="Tukey M-D Q-Q Plot").
logical scalar indicating whether to add a line to the plot. If add.line=TRUE
and plot.type="Q-Q Plot", a 0-1 line is added to the plot.
If add.line=TRUE and plot.type="Tukey M-D Q-Q Plot", a horizontal
line at \(y=0\) is added to the plot. The default value is add.line=TRUE.
scalar indicating how many significant digits to print for the test results
when plot.type="Summary" or plot.type="Test Results". If
plot.type == "Summary", the default value is
digits=2, otherwise it is
.Options$digits (i.e., the current setting of options("digits")).
numeric scalar indicating which font to use to print out the test results.
The default value is test.result.font=1. See the description of the
font argument in the help file for par for more information.
You may get better results if you use a font number that corresponds to a fixed
font (e.g., courier).
numeric scalar indicating the value of cex to use to print out the
test results. The default value is 0.9*par("cex") when
plot.type="Summary", otherwise it is par("cex").
See the description of the cex argument in the help file for
par for more information.
numeric vector indicating the value of mar to use to print out the
test results. The default value is test.result.mar=c(0, 0, 3, 0)+0.1.
See the description of the mar argument in the help file for
par for more information.
logical scalar indicating whether to add a title in the outer margin when
plot.type="Summary". The default value is add.om.title=TRUE.
character string containing the outer margin title. The default value is
om.title=NULL, which will result in a default title.
numeric scalar indicating the font to use for the outer margin. The default
value is om.font=2.
numeric scalar indicating the value of cex for the outer margin title.
The default value is 1.75 * par("cex").
numeric scalar indicating the line to place the outer margin title on. The
default value is om.line=0.5.
additional graphics parameters. See the help file for par.
plot.gofTwoSample invisibly returns the first argument, x.
The function plot.gofTwoSample is a method for the generic function
plot for the class
"gofTwoSample" (see gofTwoSample.object).
It can be invoked by calling plot and giving it an object of
class "gofTwoSample" as the first argument, or by calling
plot.gofTwoSample directly, regardless of the class of the object given
as the first argument to plot.gofTwoSample.
Plots associated with the goodness-of-fit test are produced on the current graphics device. These can be one or all of the following:
Observed distributions (plot.type="PDFs: Observed").
Observed CDFs (plot.type="CDFs: Observed").
See the help file for cdfCompare.
Q-Q Plot (plot.type="Q-Q Plot"). See the help file for
qqPlot.
Tukey mean-difference Q-Q plot (plot.type="Tukey M-D Q-Q Plot").
See the help file for qqPlot.
Results of the goodness-of-fit test (plot.type="Test Results").
See the help file for print.gofTwoSample.
See the help file for gofTest for more information.
Chambers, J. M. and Hastie, T. J. (1992). Statistical Models in S. Wadsworth & Brooks/Cole.
gofTest, gofTwoSample.object,
print.gofTwoSample,
Goodness-of-Fit Tests, plot.
# NOT RUN {
# Create an object of class "gofTwoSample" then plot the results.
# (Note: the call to set.seed simply allows you to reproduce
# this example.)
set.seed(300)
dat1 <- rnorm(20, mean = 3, sd = 2)
dat2 <- rnorm(10, mean = 1, sd = 2)
gof.obj <- gofTest(x = dat1, y = dat2)
# Summary plot (the default)
#---------------------------
dev.new()
plot(gof.obj)
# Make your own titles for the summary plot
#------------------------------------------
dev.new()
plot(gof.obj, captions = list(PDFs = "Compare PDFs",
CDFs = "Compare CDFs", QQ = "Q-Q Plot", Results = "Results"),
om.title = "Summary Plot")
# Just the Q-Q Plot
#------------------
dev.new()
plot(gof.obj, plot.type="Q-Q")
# Make your own title for the Q-Q Plot
#-------------------------------------
dev.new()
plot(gof.obj, plot.type="Q-Q", main = "Q-Q Plot")
#==========
# Clean up
#---------
rm(dat1, dat2, gof.obj)
graphics.off()
# }
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