[R] possible issue with scatterplot function in car package

[Yousri Fanous]

Great, thanks for the update!

Yousri

On Sun, May 3, 2020 at 10:54 PM Fox, John <jfox using mcmaster.ca> wrote:

> Dear Yousri,
>
> The problem with scatterplot() is now fixed in the development version
> 3.0-8 of the car package on R-Forge, which eventually will be submitted to
> CRAN. Until then, you can install the package via install.packages("car",
> repos="http://R-Forge.R-project.org")
>
> Thanks again for the bug report,
>  John
>
> > On May 3, 2020, at 4:37 AM, Yousri Fanous <yousri.fanous using gmail.com>
> wrote:
> >
> > Thank you Professor John for your answer.
> >
> > As you rightly said I am not using the ch in my example report as it has
> no bearing to the issue.
> > However it is the ch that led me to find the issue.
> > I was trying to label each point with its corresponding aa$ch value.
> > I used this code:
> >
> > scatterplot(aa$x,aa$y,smooth = FALSE, grid = FALSE, frame =
> FALSE,regLine=F)
> > text(aa$x,aa$y, labels=aa$ch,font=1 ,cex=.9,pos=3)
> >
> > The annotation was correct for 4 points but not for the (2,5) point.
> > I figured it is because it is close to the margin of the plot hence as a
> quick solution I modified xlim to shift the point away from the margin.
> > This worked for the annotation but eventually led to the issue I
> described.
> >
> > Thank you so much for your time
> >
> > Yousri Fanous
> >
> > Software Developer
> > IBM CANADA
> >
> > On Sat, May 2, 2020 at 11:47 PM Fox, John <jfox using mcmaster.ca> wrote:
> >
> > Dear Yousri,
> >
> > Yes, this is clearly a bug, and almost surely a long-standing one. We'll
> fix it in the next release of the car package.
> >
> > BTW, stringsAsFactors defaults to FALSE in R 4.0.0 (and you don't use
> the ch variable in the example). Also, although it has no bearing on the
> bug, I'd generally prefer
> >
> >         scatterplot(y ~ x, data=aa, smooth=FALSE, grid=FALSE,
> >                 frame=FALSE, regLine=FALSE, xlim=c(0, 8))
> >
> > Thank you for the bug report,
> >  John
> >
> >   -----------------------------
> >   John Fox, Professor Emeritus
> >   McMaster University
> >   Hamilton, Ontario, Canada
> >   Web: http::/socserv.mcmaster.ca/jfox
> >
> > > On May 2, 2020, at 7:30 PM, Yousri Fanous <yousri.fanous using gmail.com>
> wrote:
> > >
> > > library (car)
> > >
> > > aa <- data.frame(x=c(2,  5, 6, 7, 8),
> > > +  y=c(5,  10, 9, 12, 11),
> > > + ch=c("N",  "Q", "R", "S", "T"),
> > > + stringsAsFactors=FALSE)
> > >
> > > scatterplot(aa$x,aa$y,smooth = FALSE, grid = FALSE, frame =
> FALSE,regLine=F)
> > >
> > > Both x and y boxplots are correct
> > > and in particular the median of the x box is at 6 which is confirmed
> > >
> > >> median(aa$x)
> > > [1] 6
> > >
> > > Now I do only one addition to the scatterplot: I add xlim
> > >> scatterplot(aa$x,aa$y,smooth = FALSE, grid = FALSE, frame =
> > > FALSE,regLine=F,xlim=c(0,8))
> > >
> > > This causes the boxplot on x-axis to be in error:
> > > 1) the lower whisker starts now from zero
> > > 2) the median is between 4 and 6 and no longer at 6 as before
> > >
> > >> sessionInfo()
> > > R version 3.6.3 (2020-02-29)
> > > [1] car_3.0-7
> > >
> > >       [[alternative HTML version deleted]]
> > >
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> >
>
>

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