qqplot
Methods for Function qqplot in Package `distr'
We generalize function qqplot
from package stats to
be applicable to distribution objects. In this context,
qqplot
produces a QQ plot of two distributions, i.e.; argument x
is the distribution to be checked for compatibility, and y
is the
model ($H0$)distribution.
Graphical parameters may be given as arguments to qqplot
.
The stats function
is just the method for signature x=ANY,y=ANY
.
In all title and axis label arguments, if withSubst
is TRUE
,
the following patterns are substituted:
"%C"
 class of argument
x
"%A"
 deparsed argument
x
"%D"
 time/datestring when the plot was generated
 Keywords
 hplot, distribution
Usage
qqplot(x, y, ...)
"qqplot"(x, y, n = 30, withIdLine = TRUE, withConf = TRUE, withConf.pw = withConf, withConf.sim = withConf, plot.it = TRUE, xlab = deparse(substitute(x)), ylab = deparse(substitute(y)), ..., width = 10, height = 5.5, withSweave = getdistrOption("withSweave"), mfColRow = TRUE, n.CI = n, col.IdL = "red", lty.IdL = 2, lwd.IdL = 2, alpha.CI = .95, exact.pCI = (n<100), exact.sci =" (n<100)," nosym.pci =" FALSE," col.pci =" "orange"," lty.pci =" 3," lwd.pci =" 2," pch.pci =" par("pch")," cex.pci =" par("cex")," col.sci =" "tomato2"," lty.sci =" 4," lwd.sci =" 2," pch.sci =" par("pch")," cex.sci =" par("cex")," cex.pch =" par("cex")," col.pch =" par("col")," jit.fac =" 0," check.notinsupport =" TRUE," col.notinsupport =" "red"," with.legend =" TRUE," legend.bg =" "white"," legend.pos =" "topleft"," legend.cex =" 0.8," legend.pref =" ""," legend.postf =" ""," legend.alpha =" alpha.CI," debug =" FALSE," withsubst =" TRUE)" "qqplot"(x,="" y,="" plot.it =" TRUE," xlab =" deparse(substitute(x))," ylab =" deparse(substitute(y))," ...)<="" div="">
Arguments
 x
 object of class
"ANY"
(statsmethod) or of code"UnivariateDistribution"
; to be compared toy
.  y
 object of class
"ANY"
(statsmethod) or of class"UnivariateDistribution"
.  n
 numeric; number of quantiles at which to do the comparison.
 withIdLine
 logical; shall line
y = x
be plotted in?  withConf
 logical; shall confidence lines be plotted?
 withConf.pw
 logical; shall pointwise confidence lines be plotted?
 withConf.sim
 logical; shall simultaneous confidence lines be plotted?
 plot.it
 logical; shall be plotted at all (inherited from
qqplot
)?  xlab
 xlabel
 ylab
 ylabel
 ...
 further parameters for function
plot
 width
 width (in inches) of the graphics device opened
 height
 height (in inches) of the graphics device opened
 withSweave
 logical: if
TRUE
(for working withSweave
) no extra device is opened and height/width are not set  mfColRow
 shall default partition in panels be used  defaults to
TRUE
 n.CI
 numeric; number of points to be used for confidence interval
 col.IdL
 color for the identity line
 lty.IdL
 line type for the identity line
 lwd.IdL
 line width for the identity line
 alpha.CI
 confidence level
 exact.pCI
 logical; shall pointwise CIs be determined with exact Binomial distribution?
 exact.sCI
 logical; shall simultaneous CIs be determined with exact kolmogorov distribution?
 nosym.pCI
 logical; shall we use (shortest) asymmetric CIs?
 col.pCI
 color for the pointwise CI
 lty.pCI
 line type for the pointwise CI
 lwd.pCI
 line width for the pointwise CI
 pch.pCI
 symbol for points (for discrete mass points) in pointwise CI
 cex.pCI
 magnification factor for points (for discrete mass points) in pointwise CI
 col.sCI
 color for the simultaneous CI
 lty.sCI
 line type for the simultaneous CI
 lwd.sCI
 line width for the simultaneous CI
 pch.sCI
 symbol for points (for discrete mass points) in simultaneous CI
 cex.sCI
 magnification factor for points (for discrete mass points) in simultaneous CI
 cex.pch
 magnification factor for the plotted symbols
 col.pch
 color for the plotted symbols
 jit.fac
 jittering factor used for discrete distributions
 check.NotInSupport
 logical; shall we check if all
x
quantiles lie insupport(y)
?  col.NotInSupport
 logical; if preceding check
TRUE
color ofx
quantiles if not insupport(y)
 with.legend
 logical; shall a legend be plotted?
 legend.bg
 background color for the legend
 legend.pos
 position for the legend
 legend.cex
 magnification factor for the legend
 legend.pref
 character to be prepended to legend text
 legend.postf
 character to be appended to legend text
 legend.alpha
 nominal coverage probability
 debug
 logical; if
TRUE
additional output to debug confidence bounds.  withSubst
 logical; if
TRUE
(default) pattern substitution for titles and lables is used; otherwise no substitution is used.
Details
 qqplot
signature(x = "ANY", y = "ANY")
: functionqqplot
from package stats. qqplot
signature(x = "UnivariateDistribution", y = "UnivariateDistribution")
: produces a QQ plot for two univariate distributions.
Value

A list of elements containing the information needed to compute the
respective QQ plot, in particular it extends the elements of the
return value of function
 x
 The x coordinates of the points that were/would be plotted
 y
 The corresponding quantiles of the second distribution,
including
NA
s.  crit
 A matrix with the lower and upper confidence bounds
(computed by
qqbounds
).  err
 logical vector of length 2. (elements
qqplot
from package stats, i.e., a
list with components x
and y
for x and y coordinates
of the plotted points; more specifically it contains
crit
and err
are taken from the return
value(s) of qqbounds
).
The return value allows to recover all information used to produce the plot
for later use in enhanced graphics (e.g. with ggplot).
References
Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.
See Also
qqplot
from package stats  the standard QQ plot
function and
qqbounds
, used by qqplot
to produce confidence
intervals.
Examples
qqplot(Norm(15,sqrt(30)), Chisq(df=15))
## some discrete Distributions:
P < Pois(5)
B < Binom(size=2000,prob=5/2000)
qqplot(B,P)
## Not run:
# ## takes too much time for R CMD check ascran
# qqplot(B,P, nosym.pCI=TRUE)
# ## End(Not run)
## some LebesgueDecomposed distributions:
mylist < UnivarLebDecDistribution(discretePart=Binom(3,.3), acPart=Norm(2,2),
acWeight=11/20)
mylist2 < mylist+0.1
qqplot(mylist,mylist2)
qqplot(mylist,mylist2,exact.pCI=FALSE,exact.sCI=FALSE)
## Not run:
# ## takes too much time for R CMD check ascran
# qqplot(mylist,mylist2,nosym.pCI=TRUE)
# ## some ac. distribution with a gap
# mylist3 < UnivarMixingDistribution(Unif(0,0.3),Unif(0.6,1),mixCoeff=c(0.8,0.2))
# gaps(mylist3)
# mylist4 < UnivarMixingDistribution(Unif(0,0.3),Unif(0.6,1),mixCoeff=c(0.6,0.4))
# qqplot(mylist3,mylist4)
# qqplot(mylist3,mylist4,nosym.pCI=TRUE)
# ## End(Not run)