Displaying 20 results from an estimated 1000 matches similar to: "creation of new variables"
2008 Jan 29
1
Form Pairs of Variables for a paired t-test
Hi Users,
This is regarding the paired t-test. I have 5 variables (say) Data$v1,Data$v2,Data$v3,Data$v4,Data$v5 in my data frame. Now, I need to perform a paired t-test on all the possible 10 pairs.How do I set up the pairs table directly and pass those variables in to t-test.
Thanks in advance,
Pratap
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Now you can chat without
2007 Aug 20
3
Differentiation
Hi,
Could anyone tell me what is the command used in R to do
1. Differentiation
2. Newton Raphson method (Numerical Analysis in general...)
Are there any packages separately for this?
Thanks for your help!
BR, Shubha
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2007 Oct 10
2
Deleting the White Space in an R graph
Hi All,
Is there a way we can delete the empty white space around when we generate any graph/map using R? The final output should be onaly a picture with no white spaces all around.
Cheers,
Pratap
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2006 Sep 20
1
problem coercing truncated character vector to levels
Dear R wizes,
I have a data.frame of species abundances with column names consisting
of 4 letter codes then an underscore and a number like this:
abco_1, abco_2, abco_3, psm_1, psme_2, psme_3, etc.
I would like to get an identifier for all the abco, and psme and other
species etc.
I used
spec.fact<-substring(names(spec.count),1,4)
To make a vector of the first 4 letters of
2006 Nov 26
1
problem loading package Hmisc
Hi,
I installed the package Hmisc with the command
install.packages("Hmisc") without errors. When I try to load the
library with command library(Hmisc) I get the error
> library(Hmisc)
Error in library(Hmisc) : there is no package called 'Hmisc'
> version
_
platform i386-pc-linux-gnu
arch i386
os linux-gnu
system i386,
2006 Oct 04
1
" Error in "names<-.default"
Hi All,
Can some one explain me the following error-
" Error in "names<-.default"
'names' attribute [1199] must be the same length as the vector [17]".
Thanks,
Pratap
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2006 Oct 04
2
convert vector to matrix
Hi All,
I have vector containing 10 elements(odservations). I need to put this into a matrix, where the matrix should contain only one column.
I need this to be done using the cbind command because in the final table I should have a column of attributes( from adifferent vector) and a column of vectors from the matrix above
Please suggest me how this can be done
Thanks and
2006 Jun 14
3
A question about stepwise procedures: step function
Dear all,
I tried to use "step" function to do model selection, but I got an error massage. What I don't understand is that data as data.frame worked well for my other programs, how come I cannot make it run this time. Could you please tell me how I can fix it?
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2013 Feb 01
4
Filter according to the latest data
Hello together,
i have a data.frame, like this one:
No. Change Date
A 123 final 2013-01-15
B 123 error 2013-01-16
C 123 bug fixed 2013-01-17
D 111 final 2013-01-12
and now a want a new data.frame which includes
2006 Aug 23
5
two density curves in one plot?
Hello,
I was wondering if I can plot two curves I get from "density(data)" into
one plot. I want to compare both.
With the following commad, I just get one curve plotted:
plot( density(mydata) )
Sorry for this stupid question but I could not find a solution until now...
Antje
2006 Sep 27
2
Histogram
Dear all,
I want to design a histogram and I need to have the frequency at certain
points. For example I have the following 2 columns:
*X Y*
0.1 25
0.4 22
0.45 11
0.55 21
I want the chart to have 4 columns. First column is from 0.0-0.1 (on X) and
frequency is 25. Next colum is wider and form 0.1-0.4 with 22 frequency.
Next column is narrow with 11 frequency and the last column is
2006 Aug 23
1
covariance matrix of predictions
Hi !
I am trying to get at the covariance of the predictions of a linear model. Suppose the we have:
> x<-runif(1000)
> y<-2 + 25x*x +rnorm(1000)
> lm1 <-lm(y~x, data = data.frame(y = y, x=x))
> x.pred <-runif(10)
> y.hat <- predict(lm1, newdata = data.frame(x=x.pred))
I was wondering how to get an estimate of the covariance of y.hat which would be a 10 x 10
2006 Sep 30
3
Textmate project drawer: is there a Windows alternative?
I was reading about the project drawer feature in Textmate, which is Mac
only.
Is there a similar feature in a Windows based text editor that works with R.
This feature sounds really useful.
Thanks,
Graham
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2006 Oct 27
2
Multivariate regression
Hi,
Suppose I have a multivariate response Y (n x k) obtained at a set of
predictors X (n x p). I would like to perform a linear regression taking
into consideration the covariance structure of Y within each unit - this
would be represented by a specified matrix V (k x k), assumed to be the same
across units. How do I use "lm" to do this?
One approach that I was thinking of
2006 Aug 04
2
plotting picture data
Hi R users
I have a dataset which represents points that are market by patients as the
source of pain.
Basically the patients indicates by a cross on a chest pictures where he/she
thinks is the
source of pain. The data was then digitalized by divinding the chest into
small squares and each
square was give value 1 if it was the center 2 if it was touched by the
markings and 3 if it was not
2006 Sep 29
6
List-manipulation
Hi,
Sorry for the question, I know it should be basic knowledge but I'm
struggling for two hours now.
How do I select only the first entry of each list member and ignore the
rest?
So for
> $"121_at"
> -113691170
> $"1255_g_at"
> 42231151
> $"1316_at"
> 35472685 35472588
> $"1320_at"
> -88003869
2006 Jun 14
2
Saving R graphics with version 2.3.1
HI !
I?ve installed the latest R version (2.3.1) and I?ve had problems to
save my graphics as JPEG, PNG and the others available formats.
R saves the file with no extension. Then, I have to open this file
using an image visualizer and save it as PNG, for instance.
Previous R versions work without problems.
Has everyone had a similar problem?
Is it a bug of R 2.3.1?
Thanks in advance.
Ilka
2006 Aug 26
1
Implementing EM Algorithm in R!
Hi All,
I need some help in how one can implement maximumlikelihood estimation for
models with discrete hidden variables in EM in R.
Regards
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2007 Oct 29
3
using survfit
hie
when i use plot.survfit to plot more than one graph why I only see the last graph how do i see the other graphs.for example
n=20
n1=n/2
n2=n/4
a11=4;a12=4 ;a21=4 ;a22=4
t1<-array(1,c(n1))
t2<-array(2,c(n1))
treatgrp=matrix(c(t1,t2))
2006 Sep 20
8
Statitics Textbook - any recommendation?
I would like to buy a basic statistics book (experimental design,
sampling, ANOVA, regression, etc.) with examples in R. Or download it
in PDF or html format.
I went to the CRAN contributed documentation, but there were only R
textbooks, that is, textbooks where R is the focus, not the
statistics. And I would like to find the opposite.
Other text I am trying to find is multivariate data