Displaying 20 results from an estimated 1000 matches similar to: "Robust Statistics for Outlier Detection"
2010 Dec 22
5
regression
Hi dear all,
suppose that s is a statistic code;
i have a matrix (x) which has 7 columns (1=x1,2=x23=x3,4=x4,5=x5,6=x6
and7=y)
and has 20 rows. i want to do linear reggression like
reg<-lm(x[,7]~1+x[,1]+x[,2]+.......+x[,6])
but i want to do delete i th row for nrows times and create regression model
like above and compute each models' "s" statistics and list them. but i
could
2011 Mar 17
4
A question about list
Hi dear all,
It may be a simple question, i have a list output with different number of
elements as following;
[[1]]
[1] 0.86801402 -0.82974691 0.39746666 -0.98566707 -4.96576856 -1.32056754
[7] -5.54093319 -0.07600462 -1.34457280 -1.04080125 1.62843297 -0.20473912
[13] 0.30659907 2.66908117 2.53791837 0.53788013 -0.57463077 0.27708874
[19] -2.94233200 1.54565643 -6.83694100
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 Dec 24
3
selection of outputs from the function
Hi Dear All,
This is a function which contains Covariance Ratio and Likelihood Distance
values (CVRi, LDi). i want to compute the all row's values, that is run this
function for nrow(X) times. The X and Y matrices are;
2010 Nov 16
2
Counting
Hi dear all,
i have a data (data.frame) which contain y and x coloumn(i.e.
y x
1 0.58545723 0.15113102
2 0.02769361 -0.02172165
3 1.00927527 -1.80072610
4 0.56504053 -1.12236685
5 0.58332337 -1.24263981
6 -1.70257274 0.46238255
7 -0.88501561 0.89484429
8 1.14466282 0.34193875
9 0.58827457 0.15923694
10 -0.79532232 -1.44193770 )
i changed
2011 Mar 20
2
Why unique(sample) decreases the performance ?
Hi,
I' am interested in differences between sample's result when samples consist
of full elements and consist of only distinct elements. When sample consist
of full elements it take about 120 sec., but when consist of only distinct
elements it take about 4.5 or 5 times more sec. I expected that opposite of
this result, because unique(sample) has less elements than full sample. Code
as
2011 Jan 17
1
Problem about for loop
Hi everyones, my function like;
e <- rnorm(n=50, mean=0, sd=sqrt(0.5625))
x0 <- c(rep(1,50))
x1 <- rnorm(n=50,mean=2,sd=1)
x2 <- rnorm(n=50,mean=2,sd=1)
x3 <- rnorm(n=50,mean=2,sd=1)
x4 <- rnorm(n=50,mean=2,sd=1)
y <- 1+ 2*x1+4*x2+3*x3+2*x4+e
x2[1] = 10 #influential observarion
y[1] = 10 #influential observarion
data.x <- matrix(c(x0,x1,x2,x3,x4),ncol=5)
data.y
2007 Feb 06
8
setting enviroment variable
I have a ror project which has been productized. There are several web
sites in one ror project
I need to set an "enviroment variable" to run different sites, can I do
that using mongrel? I tried to use mongrel''s -S option and set the
enviroment variable in that file but it seems mongrel runs that file
after it calls enviroment.rb
I also used apache''s
2016 Oct 19
3
sieve sending vacation message from vmail@ns1.domain.tld
Op 19-10-2016 om 13:47 schreef Matthew Broadhead:
> i am not 100% sure how to give you the information you require.
>
> my current setup in /etc/postfix/master.cf is
> flags=DRhu user=vmail:mail argv=/usr/libexec/dovecot/deliver -d
> ${recipient}
> so recipient would presumably be user at domain.tld? or do you want the
> real email address of one of our users? is there
2010 Nov 30
3
Outlier statistics question
I have a statistical question.
The data sets I am working with are right-skewed so I have been
plotting the log transformations of my data. I am using a Grubbs Test
to detect outliers in the data, but I get different outcomes depending
on whether I run the test on the original data or the log(data). Here
is one of the problematic sets:
fgf2p50=c(1.563,2.161,2.529,2.726,2.442,5.047)
2005 Feb 25
2
outlier threshold
For the analysis of financial data wih a large variance, what is the best way to select an outlier threshold?
Listed below, is there a best method to select an outlier threshold and how does R calculate it?
In R, how do you find the outlier threshold through an interquartile range?
In R, how do you find the outlier threshold using the hist command?
In R, how do you find the outlier threshold
2012 Feb 09
1
Outlier removal techniques
Hello,
I need to analyse a data matrix with dimensions of 30x100.
Before analysing the data there is, however, a need to remove outliers from
the data.
I read quite a lot about outlier removal already and I think the most common
technique for that seems to be Principal Component Analysis (PCA). However,
I think that these technqiue is quite subjective. When is an outlier an
outlier?
I uploaded
2000 Apr 21
1
outlier detection methods in r?
hi -
if I sample from a normal distribution with something like
n100<-rnorm(100,0,1)
and add an outlier with
n100[10]<-4
then
qqnorm(n100)
visually shows the point 4 as an outlier
and calculating the probablity of a value of 4 or bigger in 100 samples of norm(0,1)
gives
> 1-exp(log(pnorm(4,0,1))*100)
[1] 0.003162164
If I have more than 1 sample above outlier threshold the math is a
2004 Jun 30
1
outlier tests
I have been learning about some outlier tests -- Dixon
and Grubb, specifically -- for small data sets. When
I try help.start() and search for outlier tests, the
only response I manage to find is the Bonferroni test
avaiable from the CAR package... are there any other
packages the offer outlier tests? Are the Dixon and
Grubb tests "good" for small samples or are others
more
2009 Feb 14
2
implementing Grubbs outlier test on a large dataframe
Hi!
I'm trying to implement an outlier test once/row in a large dataframe.
Ideally, I'd do this then add the Pvalue results and the number flagged as
an outlier as two new separate columns to the dataframe. Grubbs outlier
test requires a vector and I'm confused how to make each row of my dataframe
a vector, followed by doing a Grubbs test for each row containing the vector
of numbers
2010 Jul 14
1
randomForest outlier return NA
Dear R-users,
I have a problem with randomForest{outlier}.
After running the following code ( that produces a silly data set and builds
a model with randomForest ):
#######################
library(randomForest)
set.seed(0)
## build data set
X <- rbind( matrix( runif(n=400,min=-1,max=1), ncol = 10 ) ,
rep(1,times= 10 ) )
Y <- matrix( nrow = nrow(X), ncol = 1)
for( i in (1:nrow(X))){
2005 Aug 04
1
some thoughts on outlier detection, need help!
Dear listers:
I have an idea to do the outlier detection and I need to use R to
implement it first. Here I hope I can get some input from all the
guru's here.
I select distance-based approach---
step 1:
calculate the distance of any two rows for a dataframe. considering
the scaling among different variables, I choose mahalanobis, using
variance as scaler.
step 2:
Let k be the number of
2009 Sep 12
1
medcouple-based outlier detection in R
I need to detect outliers in a large data set which is highly right-skewed. I plan to use medcouple-based outlier detection. Is there any support for medcouple-based outlier detection in R? Are there any other routines in R to perform outlier detection in highly right-skewed data?
Manuj Sharma
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2007 Mar 28
0
Outlier detection with the dprep library
Hi.
The dprep library has at least three different methods for outlier
detection: baysout, mahaout, robout.
I wanted to test them on a very simple data set:
vrmat<-cbind((1:22),c(8,14,14,17,21,20,27,23,25,33,31,32,30,36,37,40,42,44,52,61,81,265))
As you can see by eyeballing this, the last point is a very good outlier
candidate, and maybe the second to last point, too. Anyway, I
2011 Nov 15
0
Forescasting using predict() in an object of class arimax when there is an outlier IO in the model.
Forescasting using predict() in an object of class arimax when there is an
outlier IO in the model.
Hi R users
I have a problem when a use the predict() method in an object of class
arimax ( These objects are the results of the implementation of the function
arimax() from the TSA library) . The object is a model of a time series in
which I identified an IO oulier at the element 33 of the serie