> Tukey divides the points into three groups, not the x and y values
separately.
> I'll try to get hold of the book for a direct quote, might take a couple
of days.
Ah well, I can't get it for a week. But the fact that it's often called
Tukey's three group line (try a search on *tukey three group
Tukey divides the points into three groups, not the x and y values
separately.
I'll try to get hold of the book for a direct quote, might take a couple of
days.
On Mon, May 29, 2017 at 8:40 AM, Duncan Murdoch
wrote:
> On 27/05/2017 9:28 PM, GlenB wrote:
>
>> Bug: stats::line() does not produc
On 27/05/2017 9:28 PM, GlenB wrote:
Bug: stats::line() does not produce correct Tukey line when n mod 6 is 2 or
3
Example: line(1:9,1:9) should have intercept 0 and slope 1 but it gives
intercept -1 and slope 1.2
Trying line(1:i,1:i) across a range of i makes it clear there's a cycle of
length
Thanks for all your responses. The issue seems to be more complex than
I thought. Here is the output of Sys.info() and sessionInfo() on my
GNU/Linux machine (Ubuntu 16.04.02 LTS):
R> a <- 1234568.01 + c(0:1)
R> a
[1] 1234568 1234569
R> summary(a)
Min. 1st Qu. MedianMean 3rd Qu.Max.
1234
Might this be related to the Linux version? I'm testing on one of our
university servers, and they tend to be deprived of regular updates
sometimes... (Dirk, sorry for sending you this twice.)
> Sys.info()
sysname
"Linux"
Weird, because the output of Windows is actually correct. The exact mean of
a is 1234568.51, which rounds to 1234569.
I can reproduce the Windows output on a Windows machine. My Debian server
has R 3.3.1 , and there I can reproduce your output using:
> summary(a, digits = 8)
Min. 1st Qu. Medi
On 28 May 2017 at 17:37, Arne Henningsen wrote:
| Dear all
|
| I am happy that summary.default() no longer rounds since R 3.4.0.
|
| However, in R 3.4.0, in a few cases, print.summaryDefault() rounds the
| mean value (and the median value) differently on my GNU/Linux machine
| and on my colleagu
Dear all
I am happy that summary.default() no longer rounds since R 3.4.0.
However, in R 3.4.0, in a few cases, print.summaryDefault() rounds the
mean value (and the median value) differently on my GNU/Linux machine
and on my colleague's MS-Windows machine. Here is a small (simplified)
reproducib
Can confirm this in R 3.4.0 :
end <- 6:100
res <- lapply(end, function(i) line(1:i,1:i))
absresid <- sapply(res, function(i) mean(abs(resid(i
plot(absresid, type = "h")
coefs <- sapply(res, coef)
plot(coefs[1,], coefs[2,])
> sessionInfo()
R version 3.4.0 (2017-04-21)
Platform: x86_64-w64-ming
Bug: stats::line() does not produce correct Tukey line when n mod 6 is 2 or
3
Example: line(1:9,1:9) should have intercept 0 and slope 1 but it gives
intercept -1 and slope 1.2
Trying line(1:i,1:i) across a range of i makes it clear there's a cycle of
length 6, with four of every six correct.
Bu
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