Displaying 20 results from an estimated 20 matches for "hempelmann".
2005 Oct 31
2
nls() fit to Kahnemann/ Tversky function
...ient
matrix error, so I tried the Golub-Pereyra algorithm for partially
linear least-squares.
It also seems the nls model tries to find ten different gammas, but
I want only one single gamma parameter for the function. I appreciate
your help and support. Thank you.
sol lucet omnibus
Mark Hempelmann
2004 Dec 12
1
firefox and R 201
...doing wrong?
closing and reopening firefox won't help, since the browser then asks me to create a new profile. maybe, firefox and R
(interacting with java) are conflicting? i couldn't find any help entry, so i am sorry if this problem was addressed
earlier.
R forever!
viele gr????e
mark hempelmann
universit??t bielefeld
2005 Sep 09
1
regression with restrictions - optimization problem
...70 <- a70
finalreg <- reg70
}
}
print(final70)
summary(finalreg)
Maybe a better approach works with optim(stats) or dfp(Bhat), but I
have no idea how to correctly approach such a restricted optimization
problem.
Thank you su much for your help and support.
Mark Hempelmann
2006 Mar 25
2
pairwise combinatons of variables
Dear WizaRds,
although this might be a trivial question to the community, I was unable to
find anything solving my problem in the help files on CRAN. Please help.
Suppose I have 4 variables and want to use all possible combinations:
1,2
1,3
1,4
2,3
2,4
3,4
for a further kmeans partitioning.
I tried permutations() of package e1071, but this is not what I need. Thank you
for your help and
2007 Jan 10
2
select subsets in data frame
Dear WizaRds!
A trivial question indeed on selecting subsets in data frames. I am
sorry. Unfortunately, I did not find any helpful information on the
introduction, searched the help archive and read in introductory books.
Please help:
I want to select column "KB" which is read via read.csv2 as a data.frame
into d. I checked that it is indeed a data.frame object and included the
2006 Jul 07
2
Multistage Sampling
Dear WizaRds, dear Thomas,
First of all, I want to tell you how grateful I am for all your
support. I wish I will be able to help others along one day the same way
you do. Thank you so much. I am struggling with a multistage sampling
design:
library(survey)
multi3 <- data.frame(cluster=c(1,1,1,1 ,2,2,2, 3,3), id=c(1,2,3,4,
1,2,3, 1,2),
nl=c(4,4,4,4, 3,3,3, 2,2), Nl=c(100,100,100,100,
2006 Jun 28
1
persp/ scatterplot3d
Dear WizaRds,
I would like to create a 3d-plot with persp(). I sampled 17 points
with xyz-coordinates (real-life example!), representing the peaks of the
whole plane with "zero coordinates" x=3,y=3,z=3. My intention is to show
which entries are above or below the "zero" level with persp() on a
nicely created grid. I also tried scatterplot3d(), but, alas, I am
unable
2007 Jul 14
1
return() in nested functions
Dear WizaRds,
After consulting different sources I am still unable to understand the
correct use of return() in nested functions. To illustrate the problem:
f <- function(x,y,type){
est1<-function(x,y){
z=x+y
out(x,y,z)}
est2<-function(x,y){
z=x*y
out(x,y,z)}
out<-function(x,y,z)
return(x,y,z)
if (type=="est1") est1(x,y)
if (type=="est2") est2(x,y)
}
2006 Jan 08
1
Clustering and Rand Index - VS-KM
Dear WizaRds,
I have been trying to compute the adjusted Rand index as by Hubert/
Arabie, and could not correctly approach how to define a partition
object as in my last request yesterday.
With package fpc I try to work around the problem, using my original data:
mat <- matrix( c(6,7,8,2,3,4,12,14,14, 14,15,13,3,1,2,3,4,2,
15,3,10,5,11,7,13,6,1, 15,4,10,6,12,8,12,7,1), ncol=9, byrow=T )
2007 Nov 24
1
Indexing and partially replacing 99, 999 in data frames
Dear WizaRds,
unfortunately, I have been unable to replace the '99' and '999' entries in
library(UsingR)
attach(babies)
as definitions for missing values NA, because sometimes the 99 entry is
indeed a correct value. Usually, or so I thought, NAs can
easily replace a, say, 999 entry via
mymat[mymat==999] <- "yodl"
in a matrix or data frame. Alas, the babies'
2007 Jan 27
1
Conditional Selection of Columns for Tables
Dear Wizards -
Thank you so much for your help. That was exactly what I was looking
for. Now, I have been working on conditional selection of columns in a
data frame. My goal is to calculate the total revenue per sales
representative per status in a table. I have come to a complete stop:
Let's say, we have a data.frame called df with several columns and a
number of rows:
df <-
2006 Jan 07
1
Clustering and Rand Index
Dear WizaRds,
I am trying to compute the (adjusted) Rand Index in order to comprehend
the variable selection heuristic (VS-KM) according to Brusco/ Cradit
2001 (Psychometrika 66 No.2 p.249-270, 2001).
Unfortunately, I am unable to correctly use
cl_ensemble and cl_agreement (package: clue). Here is what I am trying
to do:
library(clue)
## Let p1..p4 be four partitions of the kind
2006 Jun 05
1
Survey - twophase
Dear WizaRds,
I am struggling with the use of twophase in package survey. My goal
is to compute a simple example in two phase sampling:
phase 1: I sample n1=1000 circuit boards and find 80 non functional
phase 2: Given the n1=1000 sample I sample n2=100 and find 15 non
functional. Let's say, phase 2 shows this result together with phase 1:
...................phase1........
2006 Jun 18
1
Post Stratification
Dear WizaRds,
having met some of you in person in Vienna, I think even more fondly
of this community and hope to continue on this route. It was great
talking with you and learning from you. Thank you. I am trying to work
through an artificial example in post stratification. This is my dataset:
library(survey)
age <- data.frame(id=1:8, stratum=rep(
2005 Jun 16
1
Survey - Cluster Sampling
Dear WizaRds,
I am struggling to compute correctly a cluster sampling design. I want
to do one stage clustering with different parametric changes:
Let M be the total number of clusters in the population, and m the
number sampled. Let N be the total of elements in the population and n
the number sampled. y are the values sampled. This is my example data:
clus1 <-
2005 May 26
1
Survey and Stratification
Dear WizaRds,
Working through sampling theory, I tried to comprehend the concept of
stratification and apply it with Survey to a small example. My question
is more of theoretic nature, so I apologize if this does not fully fit
this board's intention, but I have come to a complete stop in my efforts
and need an expert to help me along. Please help:
age<-matrix(c(rep(1,5), rep(2,3),
2007 Nov 25
1
Package Building under Windows with MikTeX 2.6
Dear WizaRds,
I wrote a small function in R and would like to create a package. The
necessary documentation is done, Rtools etc. are installed and I am
still unable to complete the process under Windows. I did extensive
research in the archives and read the Murdoch-Sutherland website on the
Rtools and MikTeX hints. I realize that I understand only half or less
of what is said there
2005 Jun 24
9
R demos
Hi All,
I am currently preparing some form of slideshow introducing R and its
capabilities for some colleagues. The thing will be about 30 mins, and
I'd like to have some "pretty pictures" and some "amazing facts" (I'm
trying to sell, obviously :)).
Can I ask if it's possible to easily retrieve a gross figure of the
number of functions in R considering the
2006 Mar 23
0
kmeans Clustering
Dear WizaRds,
My goal is to program the VS-KM algorithm by Brusco and Cradit 01 and I have
come to a complete stop in my efforts. Maybe anybody is willing to follow my
thoughts and offer some help.
In a first step, I want to use a single variable for the partitioning process.
As the center-matrix I use the objects that belong to the cluster I found with
the hierarchial Ward algorithm. Then,
2006 Jul 11
0
Two Phase Sampling
Dear WizaRds,
I tried to construct a two-phase sampling design in Survey just the way
I hoped understood in Vienna - I was wrong. I think I am too stupid to
create the correct subset for phase 2. Phase1: Sample 1000 parts with 80
defective. Phase2: Sample 100 parts out of these 1000 with 15
defective. 0:ok, 1:defunct. The table below gives the conditional
sampling values.
Please help me: