# 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 (\(H_0\)-)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/date-string when the plot was generated

- Keywords
- hplot, distribution

##### Usage

```
qqplot(x, y, ...)
# S4 method for UnivariateDistribution,UnivariateDistribution
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
```

##### Arguments

- x
object of class

`"ANY"`

(stats-method) or of code`"UnivariateDistribution"`

; to be compared to`y`

.- y
object of class

`"ANY"`

(stats-method) 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
x-label

- ylab
y-label

- …
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 with`Sweave`

) 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 in`support(y)`

?- col.NotInSupport
logical; if preceding check

`TRUE`

color of`x`

-quantiles if not in`support(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")`

: function`qqplot`

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 `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

The x coordinates of the points that were/would be plotted

The corresponding quantiles of the second distribution,
*including NAs*.

A matrix with the lower and upper confidence bounds
(computed by `qqbounds`

).

logical vector of length 2.

##### 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

```
# NOT RUN {
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 --as-cran
qqplot(B,P, nosym.pCI=TRUE)
# }
# NOT RUN {
## some Lebesgue-Decomposed 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 --as-cran
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)
# }
```

*Documentation reproduced from package distr, version 2.7.0, License: LGPL-3*