Displaying 20 results from an estimated 10000 matches similar to: "using jackknife in linear models"
2010 Nov 25
2
delete-d jackknife
Hi dear all,
Can aynone help me about delete-d jackknife
usually normal jackknife code for my data is:
n <- nrow(data)
y <- data$y
z <- data$z
theta.hat <- mean(y) / mean(z)
print (theta.hat)
theta.jack <- numeric(n)
for (i in 1:n)
theta.jack[i] <- mean(y[-i]) / mean(z[-i])
bias <- (n - 1) * (mean(theta.jack) - theta.hat)
print(bias)
but how i can apply delete-d jackknife
2012 Dec 27
2
Bootstrap
Hola, buenas tardes
estoy intentando hacer un bootstrap de un modelo, pero me da el siguiente
error:
"Error in FUN(newX[, i], ...) :
unused argument(s) (list(age = c(33, 47, 49, 56, 60, 64, 64, 66, 68, 69,
71, 71, 72, 73, 74, 75, 75, 76, 78, 81, 83, 83, 36, 43, 46, 47, 49, 49, 51,
51, 52, 52, 53, 54, 54, 54, 55, 56, 56, 57, 57, 58, 58, 58, 58, 59, 59, 60,
61, 62, 63, 64, 65, 65, 66, 66,
2006 Apr 11
4
Bootstrap and Jackknife Bias using Survey Package
Dear R users,
I?m student of Master in Statistic and Data analysis, in New University of Lisbon. And now i?m writting my dissertation in variance estimation.So i?m using Survey Package to compute the principal estimators and theirs variances.
My data is from Incoming and Expendire Survey. This is stratified Multi-stage Survey care out by National Statistic Institute of Mozambique. My domain of
2007 Mar 27
1
Jackknife estimates of predict.lda success rate
Dear all
I have used the lda and predict functions to classify a set of objects
of unknown origin. I would like to use a jackknife reclassification to
assess the degree to which the outcomes deviate from that expected by
chance. However, I can't find any function that allows me to do this.
Any suggestions of how to generate the jackknife reclassification to
assess classification accuracy?
2010 Nov 14
2
jackknife-after-bootstrap
Hi dear all,
Can someone help me about detection of outliers using jackknife after
bootstrap algorithm?
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2011 Apr 19
1
How to Extract Information from SIMEX Output
Below is a SIMEX object that was generated with the "simex" function from the
"simex" package applied to a logistic regression fit. From this mountain of
information I would like to extract all of the values summarized in this
line:
.. ..$ variance.jackknife: num [1:5, 1:4] 1.684 1.144 0.85 0.624 0.519 ...
Can someone suggest how to go about doing this? I can extract the
2012 Nov 14
2
Jackknife in Logistic Regression
Dear R friends
I´m interested into apply a Jackknife analysis to in order to quantify the
uncertainty of my coefficients estimated by the logistic regression. I´m
using a glm(family=’binomial’) because my independent variable is in 0 - 1
format.
My dataset has 76000 obs, and I´m using 7 independent variables plus an
offset. The idea involves to split the data in let’s say 5 random subsets
and
2005 Nov 08
1
Poisson/negbin followed by jackknife
Folks,
Thanks for the help with the hier.part analysis. All the problems
stemmed from an import problem which was solved with file.chose().
Now that I have the variables that I'd like to use I need to run some
GLM models. I think I have that part under control but I'd like to use
a jackknife approach to model validation (I was using a hold out sample
but this seems to have fallen out
2003 Apr 16
2
Jackknife and rpart
Hi,
First, thanks to those who helped me see my gross misunderstanding of
randomForest. I worked through a baging tutorial and now understand the
"many tree" approach. However, it is not what I want to do! My bagged
errors are accpetable but I need to use the actual tree and need a single
tree application.
I am using rpart for a classification tree but am interested in a more
unbaised
2003 May 30
1
bootstrapping data.frame and matrix
Dear All,
When bootstrapping a statistics based on more than one vector, from a
data.frame or a matrix object, it looks like I am not able to pass the
data to R. What am I doing wrong?
I use the library "bootstrap".
Here is an example with a data.frame called "data"
"boot2_bootstrap(data, theta, nboot)
I get the following error message:
Error in inherits(x,
2006 Oct 24
1
Variance Component/ICC Confidence Intervals via Bootstrap or Jackknife
I'm using the lme function in nmle to estimate the variance components
of a fully nested two-level model:
Y_ijk = mu + a_i + b_j(i) + e_k(j(i))
lme computes estimates of the variances for a, b, and e, call them v_a,
v_b, and v_e, and I can use the intervals function to get confidence
intervals. My understanding is that these intervals are probably not
that robust plus I need intervals on the
2004 Sep 21
2
Bootstrap ICC estimate with nested data
I would appreciate some thoughts on using the bootstrap functions in the
library "bootstrap" to estimate confidence intervals of ICC values
calculated in lme.
In lme, the ICC is calculated as tau/(tau+sigma-squared). So, for instance
the ICC in the following example is 0.116:
> tmod<-lme(CINISMO~1,random=~1|IDGRUP,data=TDAT)
> VarCorr(tmod)
IDGRUP = pdLogChol(1)
2005 Feb 24
4
r: functions
hi all
i have a function that uses two inputs, say xdata and ydata. An example
is the following,
simple1<-function(xdata,ydata)
{
ofit<-lm(ydata~xdata)
list(ofit)
}
say i use arbitray number for xdata and ydata such that
D =
x1 x2 y
1 1 10
2 6 6
3 10 7
x<-D[,1:2]
and
y<-D[,3]
if one uses these inputs and rund the program we get the following:
>simple(xdata=x,ydata=y)
2005 Dec 09
1
R-help: gls with correlation=corARMA
Dear Madams/Sirs,
Hello. I am using the gls function to specify an arma correlation during
estimation in my model. The parameter values which I am sending the
corARMA function are from a previous fit using arima. I have had some
success with the method, however in other cases I get the following error
from gls: "All parameters must be less than 1 in absolute value". None
of
2010 Feb 10
2
Total least squares linear regression
Dear all,
After a thorough research, I still find myself unable to find a function
that does linear regression of 2 vectors of data using the "total least
squares", also called "orthogonal regression" (see :
http://en.wikipedia.org/wiki/Total_least_squares) instead of the
"ordinary least squares" method. Indeed, the "lm" function has a
2005 May 31
1
Solved: linear regression example using MLE using optim()
Thanks to Gabor for setting me right. My code is as follows. I found
it useful for learning optim(), and you might find it similarly
useful. I will be most grateful if you can guide me on how to do this
better. Should one be using optim() or stats4::mle?
set.seed(101) # For replicability
# Setup problem
X <- cbind(1, runif(100))
theta.true <- c(2,3,1)
y <- X
2008 Sep 10
3
writing simple function through script
Hi all,
I try to write a simple function in a script. The script is as follows
yo<-function(Xdata)
{
n<-length(Xdata[,1])
Lgm<-nls(formula=LgmFormula,
data=Xdata,
start=list(a=1500,b=0.1),weights=Xdata$Qe)
return(Lgm)
}
After the execution of the script, when I call the function yo on data
called NC60.DATA I get an error.
#yo(NC60.DATA)
Erreur dans eval(expr, envir, enclos)
2004 Mar 02
0
Jackknife after bootstrap influence values in boot package?
Is there a routine in the boot package to get the jackknife-after-
bootstrap influence values? That is, the influence values of
a jackknife of the bootstrap estimates?
I can see how one would go about it from the jack.after.boot code, but that
routine only makes pretty pictures.
It wouldn't be hard to write, but I find it hard to believe this
isn't part of the package already.
Thanks
2012 Mar 04
0
Jackknife for a 2-sample dispersion test
Hi All,
I'm not able to figure out how to perform a Jackknife test for a 2-sample
dispersion test in R. Is there a built-in function to perform this or do we
have to take a step by step approach to calculate the test statistic?
Any help would be awesome.
Thanks!
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2007 Dec 31
0
Optimize jackknife code
Hi,
I have the following jackknife code which is much slower than my colleagues C code. Yet I like R very much and wonder how R experts would optimize this.
I think that the for (i in 1:N_B) part is bad because Rprof() said sum() is called very often but I have no idea how to optimize it.
#O <- read.table("foo.dat")$V1
O <- runif(100000);
k=100 # size of block to delete