On May 3, 2020, at 4:37 AM, Yousri Fanous <yousri.fanous at 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 at 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 at 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
[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
R version 3.6.3 (2020-02-29)
[1] car_3.0-7
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