Displaying 20 results from an estimated 9000 matches similar to: "Discourage the weights= option of lm with summarized data"
2017 Oct 09
2
Discourage the weights= option of lm with summarized data
Yes. Thank you; I should have quoted it.
I suggest to remove this text or to add the word "not" at the beginning.
Arie
On Sun, Oct 8, 2017 at 4:38 PM, Viechtbauer Wolfgang (SP)
<wolfgang.viechtbauer at maastrichtuniversity.nl> wrote:
> Ah, I think you are referring to this part from ?lm:
>
> "(including the case that there are w_i observations equal to y_i and
2017 Oct 12
4
Discourage the weights= option of lm with summarized data
OK. We have now three suggestions to repair the text:
- remove the text
- add "not" at the beginning of the text
- add at the end of the text a warning; something like:
"Note that in this case the standard estimates of the parameters are
in general not correct, and hence also the t values and the p value.
Also the number of degrees of freedom is not correct. (The parameter
2017 Dec 03
1
Discourage the weights= option of lm with summarized data
Peter,
This is a highly structured text. Just for the discussion, I separate
the building blocks, where (D) and (E) and (F) are new:
BEGIN OF TEXT --------------------
(A)
Non-?NULL? ?weights? can be used to indicate that different
observations have different variances (with the values in ?weights?
being inversely proportional to the variances);
(B)
or equivalently, when the elements of
2017 Oct 07
1
Discourage the weights= option of lm with summarized data
In the Details section of lm (linear models) in the Reference manual,
it is suggested to use the weights= option for summarized data. This
must be discouraged rather than encouraged. The motivation for this is
as follows.
With summarized data the standard errors get smaller with increasing
numbers of observations. However, the standard errors in lm do not get
smaller when for instance all weights
2017 Oct 09
0
Discourage the weights= option of lm with summarized data
AFAIR, it is a little more subtle than that.
If you have replication weights, then the estimates are right, it is "just" that the SE from summary.lm() are wrong. Somehow, the text should reflect this.
It is of some importance when you put glm() into the mix, because you can in fact get correct results from things like
y <- c(0,1)
w <- c(49,51)
glm(y~1, weights=w,
2017 Nov 28
0
Discourage the weights= option of lm with summarized data
My local R-devel version now has (in ?lm)
Non-?NULL? ?weights? can be used to indicate that different
observations have different variances (with the values in
?weights? being inversely proportional to the variances); or
equivalently, when the elements of ?weights? are positive integers
w_i, that each response y_i is the mean of w_i unit-weight
observations
2017 Nov 28
0
Discourage the weights= option of lm with summarized data
Since the three posters agree (only) that there is a bug, I propose to
file it as a bug, which is the least we can do now.
There is more to it: the only other case of a change in the Reference
Manual which I know of, is also about the weights option! This is in
coxph. The Reference Manual version 3.0.0 (2013) says about coxph:
" ... If weights is a vector of integers, then the estimated
2017 Oct 08
0
Discourage the weights= option of lm with summarized data
Ah, I think you are referring to this part from ?lm:
"(including the case that there are w_i observations equal to y_i and the data have been summarized)"
I see; indeed, I don't think this is what 'weights' should be used for (the other part before that is correct). Sorry, I misunderstood the point you were trying to make.
Best,
Wolfgang
-----Original Message-----
From:
2020 Apr 30
2
Use of MathJax (or something similar) in .Rd files
Thanks Gabor and Duncan! It works. For those interested, I added this to the beginning of the \details{} section:
\if{html}{\out{
<script id="MathJax-script" async
src="https://cdn.jsdelivr.net/npm/mathjax at 3/es5/tex-mml-chtml.js">
</script>
}}
And then I can use:
\if{html}{\out{\(B_{x(a,b)} = \int_0^x t^{a-1} (1-t)^{b-1} dt\)}}
or
2020 Apr 30
3
Use of MathJax (or something similar) in .Rd files
Hello All,
I am wondering if there has ever been any discussion/consideration given to incorporating MathJax (or something similar) into R for rendering equations in .Rd files. I know that equations are rendered beautifully in the pdf manuals, but I suspect the majority of users primarily look at the html help files when using R. While I am comfortable reading something like "B_x(a,b) =
2020 Apr 30
2
Use of MathJax (or something similar) in .Rd files
Interesting. I gave this a try, but couldn't make this work. One would have to infuse something like
<script id="MathJax-script" async
src="https://cdn.jsdelivr.net/npm/mathjax at 3/es5/tex-mml-chtml.js">
</script>
or
<script id="MathJax-script" async
src="<url-to-your-site>/mathjax/tex-chtml.js">
</script>
into
2020 May 05
1
Use of MathJax (or something similar) in .Rd files
Hi All,
After some tinkering, and with support from Duncan, I put together a package that allows for easy inclusion of MathJax equations in Rd files. The package has been submitted to CRAN, but those who want to try this out already can get it here:
https://github.com/wviechtb/mathjaxr
or in other words:
install.packages("remotes")
2012 Sep 26
3
Broken Links on http://www.r-project.org
I was not sure who I should contact about this, so I am posting this here.
There are a few broken links on the R website.
1) http://www.r-project.org/search.html -> link to the Nabble R Forum. I belive the correct/new URL should be: http://r.789695.n4.nabble.com/
2) http://www.r-project.org/other-docs.html -> link to "Auswertung ?kologischer Daten". Not sure if there is a new
2024 Oct 11
1
Error message when calling t.test() and aov() with a factor variables
> -----Original Message-----
> From: Kurt Hornik <Kurt.Hornik at wu.ac.at>
> Sent: Friday, October 11, 2024 14:18
> To: Viechtbauer, Wolfgang (NP) <wolfgang.viechtbauer at maastrichtuniversity.nl>
> Cc: r-devel <r-devel at r-project.org>
> Subject: Re: [Rd] Error message when calling t.test() and aov() with a factor
> variables
>
> >>>>>
2015 May 13
4
CRAN check for package on Sparc Solaris
Dear All,
The metafor package currently fails CRAN checks on Sparc Solaris:
http://cran.r-project.org/web/checks/check_results_metafor.html
The problem is probably due to an unintended (= stupid) use of identical() in a couple tests. I have changed that to more appropriate tests using all.equal(). However, before I resubmit the package to CRAN, I would really like to make sure that the updated
2017 May 05
6
lm() gives different results to lm.ridge() and SPSS
Hi,
Here is (I hope) all the relevant output from R.
> mean(s1$ZDEPRESSION, na.rm=T) [1] -1.041546e-16 > mean(s1$ZDIVERSITY_PA, na.rm=T) [1] -9.660583e-16 > mean(s1$ZMEAN_PA, na.rm=T) [1] -5.430282e-15 > lm.ridge(ZDEPRESSION ~ ZMEAN_PA * ZDIVERSITY_PA, data=s1)$coef ZMEAN_PA ZDIVERSITY_PA ZMEAN_PA:ZDIVERSITY_PA
-0.3962254 -0.3636026
2013 Dec 12
1
refline in forest() {metafor}
Hello all,
I am using forest.rma to plot a random effects model meta-analysis. I noticed
that refline sets a vertical line indicating the null hypothesis.
Is there a way to draw another vertical line, possibly dashed, centered on the
summary estimate?
Prof. Viechtbauer, if you happen to read this, I'd like to thank you for making
an excellent package. I have been using the metafor package
2024 Oct 11
1
Error message when calling t.test() and aov() with a factor variables
>>>>> Viechtbauer, Wolfgang (NP) writes:
> Hi all,
> Just noticed that the error that arises when calling t.test() with factors could be a bit clearer:
>> t.test(factor(c(3,1,2,4,3,5,4,5)), factor(c(2,1,2,3,4,5)))
> Error in var(x) : Calling var(x) on a factor x is defunct.
> Use something like 'all(duplicated(x)[-1L])' to test for a constant vector.
2023 Apr 25
1
xyTable(x,y) versus table(x,y) with NAs
x <- c(1, 1, 2, 2, 2, 3)
y <- c(1, 2, 1, 3, NA, 3)
> str(xyTable(x,y))
List of 3
$ x : num [1:6] 1 1 2 2 NA 3
$ y : num [1:6] 1 2 1 3 NA 3
$ number: int [1:6] 1 1 1 NA NA 1
How many (2,3)s do we have? At least one, the third entry, but the fourth
entry, (2,NA), is possibly a (2,3) so we don't know and make the count NA.
I suspect this is not the intended logic, but a
2023 Apr 25
2
xyTable(x,y) versus table(x,y) with NAs
Hi all,
Posted this many years ago (https://stat.ethz.ch/pipermail/r-devel/2017-December/075224.html), but either this slipped under the radar or my feeble mind is unable to understand what xyTable() is doing here and nobody bothered to correct me. I now stumbled again across this issue.
x <- c(1, 1, 2, 2, 2, 3)
y <- c(1, 2, 1, 3, NA, 3)
table(x, y, useNA="always")
xyTable(x, y)