Displaying 20 results from an estimated 90 matches similar to: "A stat related question"
2004 Jan 07
2
problem assigning an array to a variable in a data frame
Dear r-devel list members,
Dirk Eddelbuettel brought the following problem to my attention. The code
is abstracted from the appendix on mixed models from my R and S-PLUS Companion:
> set.seed(12345) # for reproducibility
> library(nlme)
Loading required package: lattice
> data(MathAchieve)
> data(MathAchSchool)
> attach(MathAchieve)
> mses <- tapply(SES, School,
2013 May 16
2
R looping help
Hey I'm not really sure what I should put on here, but I am having trouble
with my R code. I am trying to get the p-values, R^2s etc for a number of
different groups of variables that are all in one dataset.
This is the code:
#Stand counter
st<-1
#Collections
stands<-numeric(67)
slopes<-numeric(67)
intercepts<-numeric(67)
mses<-numeric(67)
rsquares<-numeric(67)
2002 May 02
2
problem with lme in nlme package
Dear R list members,
I've turned up a strange discrepancy between results obtained from the lme
function in the nlme package in R and results obtained with lme in S-PLUS.
I'm using version 3.1-24 of nlme in R 1.4.1 under Windows 2000, and both
S-PLUS 2000 and 6.0, again under Windows 2000.
I've noticed discrepancies in a couple of instances. Here's one, using data
from Bryk
2011 Sep 10
3
Help installing Win on MacBook Pro
My son is taking some programming courses in school and it would be very helpful if he could run Visual Studio on his Mac. I own older VB5 and Visual Studio 6 (from my old PC days).
[Embarassed] I cannot figure out how to install Wine on his Mac.
Can someone please guide me (e.g. show me all the steps I need to follow to install Wine) so that I can then install VB5 and VS6?
He's not
2012 Aug 27
1
interpret the importance output?
> importance(rfor.pdp11_t25.comb1,type=1)
%IncMSE
v1 -0.28956401263
v2 1.92865561147
v3 -0.63443929130
v4 1.58949137047
v5 0.03190940065
I wasn't entirely confident with interpreting these results based on the
documentation.
Could you please interpret?
[[alternative HTML version deleted]]
2011 May 20
2
extraction of mean square value from ANOVA
Hello,
I am randomly generating values and then using an ANOVA table to find the
mean square value. I would like to form a loop that extracts the mean square
value from ANOVA in each iteration. Below is an example of what I am doing.
a<-rnorm(10)
b<-factor(c(1,1,2,2,3,3,4,4,5,5))
c<-factor(c(1,2,1,2,1,2,1,2,1,2))
mylm<-lm(a~b+c)
anova(mylm)
Since I would like to use a loop to
2011 Nov 17
1
tuning random forest. An unexpected result
Dear Researches,
I am using RF (in regression way) for analize several metrics extract from
image. I am tuning RF setting a loop using different range of mtry, tree
and nodesize using the lower value of MSE-OOB
mtry from 1 to 5
nodesize from1 to 10
tree from 1 to 500
using this paper as refery
Palmer, D. S., O'Boyle, N. M., Glen, R. C., & Mitchell, J. B. O. (2007).
Random Forest Models
2020 Jun 24
2
Loop vectorization and unsafe floating point math
Hi llvm-dev!
We are doing some fuzzy testing using C program generators,
and one question that came up when generating a program with
both floating point arithmetic and loop pragmas was;
Is the loop vectorizer really allowed to vectorize a loop when
it can't prove that it is safe to reorder fp math, even if
there is a loop pragma that hints about a preferred width.
When reading here
2006 Aug 25
4
[LLVMdev] Built LLVM 1.8 on VC8, invalid iterator issue/fix, some questions
Hello,
I've managed to get LLVM 1.8 to build properly with MSVC8 with some
effort. Most of the changes necessary were very minor C++ usage issues;
for instance, VC8 can't deal with prototyping something that's really a
class as 'struct Foo;' or vice versa (it creates issues with matching
function signatures during linking.) Additionally, I had to do quite a few
updates to the
2007 Feb 28
1
Efficient way to repeat rows (or columns) of a matrix?
Hi.
If I have a vector, v_1, and another vector of positive integers, i_1, the
same length as v_1, then rep(v_1,i_1) will repeat v_i[j] exactly i_1[j]
times, like so:
>rep(c(1,2,3),c(3,2,1))
[1] 1 1 1 2 2 3
>
I'd like to do the same sort of thing where I replace v_1 with a matrix, and
the jth row of the matrix is repeated i_1 times.
Obviously, I could do this with for loops, like
2009 Aug 13
1
metafor random effects meta-analysis
Hello,
Great to see the new metafor package for meta-analysis.
I would like to perform a meta-analysis in which I initially calculate the intercept of the model with a nested random-effects structure. In lme, this would be
model<- lme(v3~1, random=~1|species/study, weights = varFixed(~Wt), method = "REML")
where multiple effects sizes are measured for some studies and more than
2004 May 07
1
plotting planes and lines in wireframe()
Hi R-helpers
I would like to plot some planes which are perpendicular to the x-y
plane, such as x=y. Is there a way to do this in wireframe? I realize
that I am not plotting a function of x, y since there are infinite
number of z's that satisfy the above relation.... Hmm...
Somewhat related, I would also like to plot a line in 3 d space...
Finally, if you are feeling really brave, I
2010 Oct 24
1
Optimize parameters of ODE Problem which is solved numeric
Hi,
I have a data-matrix:
> PID
sato hrs fim health
214 3 4.376430 6.582958 5
193 6 4.361825 3.138525 6
8441 6 4.205771 3.835886 7
7525 6 4.284489 3.245139 6
6806 7 4.168926 2.821833 7
5682 7 1.788707 1.212653 7
5225 6 1.651463 1.436980 7
4845 6 1.692710 1.267359 4
4552 5 1.686448 1.220539 6
2001 Jun 11
1
Additional output in cancor
Hi everyone,
Can I suggest an additional output component in cancor, from package
mva? It would be useful to have the number of canonical correlation
vectors, equivalently the rank of the covariance between x and y (label
"rank"). This would usually be min(dx, dy), where dx and dy have
already been computed for the svd function, but there might be
situations where it was less than
2010 Feb 23
1
function on all pairs of vector entries
Hello all,
Is there a way in R to compute the multivariate normal density of every pair of entries in a vector efficiently instead of using for loop?
For example
Suppose I have a vector a=c(v_1,...,v_p)=c(0.5343909, -0.7784353, -0.0568370, 1.8772838, -1.3183407, 0.8227418,...)
I want to compute density(v_i, v_j) for every pair of entries (i,j) (i!=j) in a. The joint bivariate distribution
2010 Oct 01
1
Question about Reduce
Hello!
In the example below the Reduce() function by default assigns "a" to
be the last accumulated value and "b" to be the current value in "x".
I could not find this documented anywhere as the default settings for
the Reduce() function. Does any sort of documentation for this
behavior exist?
x <- c(0,0,0,0,0,1,0,0,0,5,0,0,0,7,0,0,0,8,5,10)
2007 May 25
0
Off topic: S.E. for cross validation
Hi,
I'm performing (blocked) 10-fold cross-validation of a several time
series forecasting methods, measuring their mean squared error (MSE).
I know that the MSE_cv is the average over the 10 MSEs. Is there a way
to calculate the standard error as well?
The usual SD/sqrt(n) formula probably doesn't apply here as the 10
observations aren't independent.
Thanks,
Gad
--
Gad
2002 Dec 17
0
new version of randomForest
A new version of the randomForest package is now available on CRAN. The
DESCRIPTION is:
Package: randomForest
Title: Breiman's random forest for classification and regression
Version: 3.4-1
Depends: R (>= 1.5.0)
Author: Fortran original by Leo Breiman and Adele Cutler, R port by Andy
Liaw and Matthew Wiener.
Description: Classification and regression based on a forest of trees using
2010 Jun 18
0
Confidence interval calculation for intersection of two quadratic lines
How do I calculate the confidence interval for the value x given by the intersection of two quadratics (i.e. parabolas)?
I fit two quadratics of the form:
y = C1 + B1*x + A1*x^2
y = C2 + B2*x + A2*x^2
to two sets of points N1 and N2.
I test for whether they intersect, if they do then I calculate the roots of:
0 = (C1 - C2) + (B1 - B2)*x + (A1 - A2)*x^2
to determine where they intersect
2009 Mar 19
8
function question
Dear R Gurus:
I read somewhere that functions are considered vectors.
Is this true, please?
thanks
Edna Bell