Displaying 20 results from an estimated 500 matches similar to: "Jackknife estimates of predict.lda success rate"
2007 Apr 02
0
Plots from lda and predict.lda
Dear all
When plotting the results of lda and predict.lda, I expect the axis
dimensions to remain essentially the same - predict.lda projects new
observations onto linear discriminants. However, I am getting different
ranges of values along the x-axis when producing plots following each:
plot(lda) yields values in the range approximately -3 to +4, while
plot(predict.lda) yields values for the
2008 Dec 18
1
using jackknife in linear models
Hi R-experts,
I want to use the jackknife function from the bootstrap package onto a
linear model.
I can't figure out how to do that. The manual says the following:
# To jackknife functions of more complex data structures,
# write theta so that its argument x
# is the set of observation numbers
# and simply pass as data to jackknife the vector 1,2,..n.
# For example, to jackknife
#
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
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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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
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
2012 Nov 28
2
NRI or IDI for survival data - Hmisc package
Hi, I am trying to calculate net reclassification improvement (NRI) and Inegrated Discrimination Improvement (IDI) for a survival dataset to compare 2 risk models. It seems that the improveProb() in Hmisc package does this only for binary outcome, while rcorrp.cens() does take survival object, but doesn't output NRI or IDI. Can anyone suggest any other packages that can calculate NRI and IDI
2006 Dec 18
1
Replacing labels with symbols in biplot
Dear all
I would like to replace labels for x in biplot() with symbols (points)
that will visually illustrate different classes/groups. After an
unsuccessful search through the documents and archives, I turn to the
list for help - any suggestions that can point me in the right
direction?
Thanks
Mat Vanderklift
2012 Nov 07
2
R: net reclassification index after Cox survival analysis
Dear all,
I am interested to evaluate reclassification using net
reclassification improvement and Integrated Discrimination Index IDI after
survival analysis (Cox proportional hazards using stcox). I search a R
package or a R code that specifically addresses the categorical NRI for
time-to-event data in the presence of censored observation and, if
possible, at different follow-up time points.
I
2012 Dec 22
1
NRI reclassification table improveProb Cox
As describe in the Hmisc package's improveProb function, that function is for
binary Y. And it's best to use category-free methods.
Frank
Petergodsk wrote
> Hi
>
> I'm new to R.
>
> Is it possible to use the improveProb function to generate categorybased
> NRI using a Cox model?
> I believe I saw someone mentioning the possibility, but I can't find the
2012 Jan 17
2
net classification improvement?
Greetings,
I have generated several ROC curves and would like to compare the AUCs.
The data are cross sectional and the outcomes are binary. I am testing
which of several models provide the best discrimination. Would it be most
appropriate to report AUC with 95% CI's?
I have been looking in to the "net reclassification improvement" (see
below for reference) but thus far I can only
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 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")$V1
O <- runif(100000);
k=100 # size of block to delete
2012 Aug 15
2
store the results of two connected and "disturbed" for-loops to data.frame
Dear all,
here is a example of my problem:
/#data#
g<-c(1,1,1,2,2,2)
A<-runif(6,min=1,max=5)
B<-runif(6,min=100,max=1000)
C<-runif(6,min=30,max=31)
D<-runif(6,min=67,max=98765)
var<-cbind(A,B,C,D)
label<-colnames(var)
store<-data.frame(matrix(ncol=2))
colnames(store)=c("usedVar","prediction")
library(MASS)#get lda
for (i in c(1:4))
{
for (k in
2011 Apr 19
1
How to Extract Information from SIMEX Output
Below is a SIMEX object that was generated with the "simex" function from the
"simex" package applied to a logistic regression fit. From this mountain of
information I would like to extract all of the values summarized in this
line:
.. ..$ 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
2011 May 18
1
Help with Memory Problems (cannot allocate vector of size)
While doing pls I found the following problem
> BHPLS1 <- plsr(GroupingList ~ PCIList, ncomp = 10, data = PLSdata, jackknife =
>FALSE, validation = "LOO")
when not enabling jackknife the command works fine, but when trying to enable
jackknife i get the following error.
>BHPLS1 <- plsr(GroupingList ~ PCIList, ncomp = 10, data = PLSdata, jackknife =
>TRUE,