Displaying 20 results from an estimated 10000 matches similar to: "Problem"
2012 Apr 10
1
compare two matrices
Dear Members,
I have two estimated transition matrices and I want to compare them.
In fact I want to check the hypothesis if they come from the same process.
I tried to look for some test but all I found was independence test of
contingency tables.
The following code shows that the usual chi-squared test statistic does
not follow chisq distribution.
MCRepl <- 5000
khi12 <- rep(0,MCRepl)
2014 Mar 17
5
LD50
Quiero comparar varias dosis letales 50% (LD50) usando análisis probit. He
seguido un ejemplo que viene en paquete DRC, pero no obtengo el resultado
esperado. Lo que quiero es saber si las LD50s, son diferentes y si la
diferencias son estadísticamente significativas.
Gracias de antemano.
José Arturo
e-mail. jafarfan@uady.mx <grejon@uady.mx>
e-mail alterno. jafarfan@gmail.com
2009 Feb 19
4
type III effect from glm()
Hi all,
This could be naivety/stupidity on my part rather than a problem with model output, but here goes....
I have fitted a fairly simple model
m1<-glm(count~siteall+yrs+yrs:district,family=quasipoisson,weights=weight,data=m[x[[i]],])
I want to know if yrs (a continuous variable) has a significant unique effect in the model, so I fit a simplified model with the main effect ommitted...
2004 May 27
2
block diagonal matrix function
Hello List
I have just written a little function that takes two matrices as
arguments and returns a large matrix that is composed of the two input
matrices in upper-left position and lower-right position with a padding
value everywhere else. (function definition and toy example below). I
need nonsquare matrices and rowname() and colname() inherited appropriately.
Two questions:
(1) Is there a
2002 May 11
1
deleting invariant rows and cols in a matrix
Greetings,
I couldn't find any existing function that would allow me to scan a
matrix and eliminate invariant rows and columns so I have started to
write a simple routine from scratch. The following code fails because
the array index goes out of bounds for obvious reasons you'll see
shortly.
Start with some data
x <- read.table("myex.dat",header=T)
x
v1 v2 v3 v4 v5 id
1
2024 Apr 23
1
System GMM yields identical results for any weighting matrix
A copy of this question can be found on Cross Validated:
https://stats.stackexchange.com/questions/645362
I am estimating a system of seemingly unrelated regressions (SUR) in R.
Each of the equations has one unique regressor and one common regressor. I
am using `gmm::sysGmm` and am experimenting with different weighting
matrices. I get the same results (point estimates, standard errors and
2024 Apr 23
1
System GMM yields identical results for any weighting matrix
Generally speaking, this sort of detailed statistical question about a
speccial package in R does not get a reply on this general R
programming help list. Instead, I suggest you either email the
maintainer (found by ?maintainer) or ask a question on a relevant R
task view, such as
https://cran.r-project.org/web/views/Econometrics.html . (or any other
that you judge to be more appropriate).
2006 Jan 27
2
lme4_0.995-2/Matrix_0.995-4 upgrade introduces error messages (change management)
I'll address two issues. The first is today's error message and the other is change management for contributed packages on CRAN.
TODAY'S ERROR MESSAGE
I switched from the 0.995-1 versions of lme4 and Matrix to those referenced in the subject line this afternoon. Prior to using these packages on anything else, I applied them to code that 'worked' (provided numerical results
2008 Feb 22
3
Simultaneously summarizing many models
Dear R users,
Let?s say I have 10 models, each named m1,m2,m3..., and I would like to summarize them automatically
and simultaneously - e.g., to extract parameter estimates later on from all models; how can I do that?
I have tried:
x=1:10 #this creates some example data
y=rnorm(10)
m1=lm(x~y)
m2=lm(x~1)
sum.lms=function(x)summary(paste("m",x,sep=""))
sum.lms(1:2)
but
2011 Sep 03
2
problem in applying function in data subset (with a level) - using plyr or other alternative are also welcome
Dear R experts.
I might be missing something obvious. I have been trying to fix this problem
for some weeks. Please help.
#data
ped <- c(rep(1, 4), rep(2, 3), rep(3, 3))
y <- rnorm(10, 8, 2)
# variable set 1
M1a <- sample (c(1, 2,3), 10, replace= T)
M1b <- sample (c(1, 2,3), 10, replace= T)
M1aP1 <- sample (c(1, 2,3), 10, replace= T)
M1bP2 <- sample (c(1, 2,3), 10, replace= T)
2009 Mar 17
2
bigglm() results different from glm()
Dear all,
I am using the bigglm package to fit a few GLM's to a large dataset (3
million rows, 6 columns). While trying to fit a Poisson GLM I noticed
that the coefficient estimates were very different from what I obtained
when estimating the model on a smaller dataset using glm(), I wrote a
very basic toy example to compare the results of bigglm() against a
glm() call. Consider the
2006 Apr 23
2
distribution of the product of two correlated normal
Hi,
Does anyone know what the distribution for the product of two correlated
normal? Say I have X~N(a, \sigma1^2) and Y~N(b, \sigma2^2), and the
\rou(X,Y) is not equal to 0, I want to know the pdf or cdf of XY. Thanks
a lot in advance.
yu
[[alternative HTML version deleted]]
2010 Jun 16
2
data frame
Dear list,
I have the following problem. I have a data frame like this
CLUSTER YEAR variable Delta R_pivot
M1 2005 EC01 NA NA
M1 2006 EC01 2 NA
M1 2007 EC01 4 5
M2 2005
2006 Mar 13
3
hfsc and dropped packets
Hi,
I''m trying to get a handle on hfsc. Here is my configuration:
root@jmnrouter:/jmn# tc class show dev vlan1
class hfsc 1: root
class hfsc 1:1 parent 1: ls m1 0bit d 0us m2 225000bit ul m1 0bit d 0us m2
225000bit
class hfsc 1:10 parent 1:1 rt m1 191000bit d 25.0ms m2 135000bit ls m1 0bit
d 0us m2 135000bit ul m1 0bit d 0us m2 225000bit
class hfsc 1:20 parent 1:1 rt m1 22008bit d
2004 Jul 13
1
MLE, precision
Hi, everyone
I am trying to estimate 3 parameters for my survival
function. It's very complicated. The negative
loglikelihood function is:
l<- function(m1,m2,b) -sum( d*( log(m1) + log(m2)
+ log(1- exp(-(b + m2)*t)) ) + (m1/b - d)*log(m2 +
b*exp(-(b + m2)*t) ) + m1*t - m1/b*log(b+m2) )
here d and t are given, "sum" means sum over these
two vairables.
the parameters
2012 Jan 11
3
summarizing a complex dataframe
I need some help summarizing complex data frames (small example below):
m1_1 m2_1 m3_1 m1_2 m2_2 m3_2
i1 1 1 1 2 2 2
i1 2 1 1 2 2 2
i2 2 2 1 2 2 2
For an arbitrary number of columns (say m1 ?. m199) where the column names have variable patterns,
and such that each set of columns is repeated (with potentially unique data) an
2010 Jun 17
1
big big problem
Dear list,
I'll try to be more clear in explaining my problem. I have a data frame like this called X:
CLUSTER YEAR variable value1 value2
M1 2005 EC01 NA NA
M1 2006 EC01 2 5
M1 2007
2007 Feb 27
2
Creating a contended section of bandwidth with HTB and IMQ
Hi All,
I''m trying to create a contended section of bandwidth using IMQ. I have the
imq0 device up and running, with traffic passing through it.
Firstly, I need to throttle the entire device imq0 to 2mbit/s.
I would then like to add throttle rules for individual IP addresses, allowing
them to pass up to 512kbit/s each, as long as imq0 has not reached its
2mbit/s.
The configuration
2008 Jan 29
2
add/subtract matrices, ignoring NA or missing values
Hi,
For example, given two 2x2 matrices m1 and m2. I would like to add/subtract
element by element
> m1
[,1] [,2]
[1,] NA NA
[2,] 1 2
> m2
[,1] [,2]
[1,] 1 NA
[2,] NA 2
> m1 + m2
[,1] [,2]
[1,] NA NA
[2,] NA 4
How can I ignore the NA, and get this ? Hope the solution can be extended to
subtract and modulo also.
[,1] [,2]
2010 Apr 14
5
Running cumulative sums in matrices
Dear R-helpers,
I have a huge data-set so need to avoid for loops as much as possible. Can someone think how I can compute the result in the following example (that uses a for-loop) using some version of apply instead (or any other similarly super-efficient function)?
example:
#Suppose a matrix:
m1=cbind(1:5,1:5,1:5)
#The aim is to create a new matrix with every column containing the