Displaying 20 results from an estimated 5000 matches similar to: "'skewing' a normal random variable"
2006 Jul 13
1
Scalling/Centering the Data by an Index
Dear All:
I would like to center the data in 'x' by 'group'. The following code scale
the data and I have not been able to figure out how to change it so I get
the centered data.
x <- c(1, 2, 3, 4, 5, 6, 7, 8)
group <- c(1,1,1,2,2,2,2,2)
unsplit(lapply(split(x,group),scale),group)
I would appreciate your help.
Ashraf
2005 Apr 03
4
Generating a binomial random variable correlated with a normal random variable
Hi All:
I would like to generate a binomial random variable that correlates with a
normal random variables with a specified correlation. Off course, the
correlation coefficient would not be same at each run because of randomness.
I greatly appreciate your input.
Ashraf
2006 Mar 22
1
lme convergence
Dear All:
lme(sbp ~ cengirth, data = family, random= ~ 1 | familyid)
converges but
lme(sbp ~ cengirth, data = family, random= ~ cengirth | familyid)
does not.
I get the following message:
Error in lme.formula(sbp ~ cengirth, data = family, random = ~cengirth |
:
iteration limit reached without convergence (9)
The data has 488 rows and 154 familyid levels. For
2004 Dec 17
1
Confidence Intervals from Bootstrap Replications
Hi All:
I have to compute bootstrap confidence intervals, the statistic
(incremental cost effectiveness ratio) is computed from two samples
(intervention and control) of different sizes. All the bootstrap
functions that I have seen use one dataset as argument. I may go ahead
and get the desired number of bootstrap replications separately. I would
appreciate if you could point me to a source of a
2006 Mar 16
6
removing ROWS with missing values
I am trying to find out if R can recognize specific criteria for removing
rows (i.e. a prexisting function)
I have a matrix myMatrix that is 12000 by 20
I would like to remove rows from myMatrix that have:
-999 across all columns
-999 across all columns but one
-999 across all columns but two
-999 across all columns but three
-999 across all columns but four
-999 across all columns but five
2005 Aug 04
1
Where the error message comes from?
Hi all:
I get the following error message that I am not able to resolve.
Error in if (const(t, min(1e-08, mean(t)/1e+06))) { :
missing value where TRUE/FALSE needed
It appears right before the last data.frame statement.
Below is the program that simulates data from one way random effects
model and then computes normality and bootstrap confidence interval for
2005 Apr 13
2
extracting one element of correlation matrices from a list poroduced by the 'by' statement
I am producing 2X2 correlation matrices by a class variable. I need to
extract a vector of correlation coefficients only. I am doing that in a
loop (see below) but I am sure there would be a simpler way. Please
help!
> by(d1[,c(2,3)],d1[,1],cor)
d1[, 1]: 1
c e
c 1.0000000 0.1972309
e 0.1972309 1.0000000
2005 Sep 01
5
Multivariate Skew Normal distribution
> -----Original Message-----
> From: r-help-bounces at stat.math.ethz.ch
> [mailto:r-help-bounces at stat.math.ethz.ch]On Behalf Of Caio Lucidius
> Naberezny Azevedo
> Sent: 01 September 2005 12:09
> To: Help mailing list - R
> Subject: [R] Multivariate Skew Normal distribution
>
>
> Hi all,
>
> Could anyone tell me if there is any package (or function)
2006 Jul 29
0
Help with clogit in survival - conditional logistic regression
Dear All:
I have been struggling to run the conditional logistic regression on a
dataset. I am using clogit function in survival package. Here is how the
data is generated. I tried to shorted the data by using the second count
variable but still the clogit did not run. Why I am not able to run clogit
on my dataset. I appreciate any input.
Regards,
Ashraf
age <- c(rep(0,8),rep(1,8))
scc <-
2009 Aug 22
6
Fw: Re: my bootlog
Fasiha Ashraf
--- On Sat, 22/8/09, Fasiha Ashraf <feehapk@yahoo.co.in> wrote:
From: Fasiha Ashraf <feehapk@yahoo.co.in>
Subject: Re: [Xen-users] my bootlog
To: "Boris Derzhavets" <bderzhavets@yahoo.com>
Date: Saturday, 22 August, 2009, 11:12 AM
Please check what wrong here
grub.conf
title Fedora (2.6.30-rc6-tip)
root (hd0,6)
kernel
2017 Sep 26
2
build a SpatialLines object from a list
Hi Eric,
Thanks for the help.But this will not solve the problem as it will generate a list and what I need is an object of class sp using SpatialLine function from sp package.So, I need to convert each matrix to coordinates and then to a line and then to a spatial line as figured in the code.
My data structure is a list of 141 matrices.Each matrix represents coordinates of the river lines
2017 Sep 25
0
build a SpatialLines object from a list
Hi Ashraf,
It is not obvious to me what your structures are but one problem in your
function is the assignment tt1 <- SpatialLines(list(tt[[i]])).
This will set tt1 to just have one item.
Consider the following
test.func <- function(x) {
tt1 <- list()
for ( i in ... ) {
...
tt1[[i]] <- SpatialLines(tt[[i]])
}
return(tt1)
}
HTH,
Eric
On Mon, Sep 25,
2011 Nov 03
3
Plotting skewed normal distribution with a bar plot
Hi,
I need to create a plot (type = "h") and then overlay a skewed-normal
curve on this distribution, but I'm not finding a procedure to accomplish
this. I want to use the plot function here in order to control the bin
distributions.
I have explored the sn library and found the dsn function. dsn uses known
location, scaling and shape parameters associated with a given input
2008 Aug 10
2
detect if data is normal or skewed (without a boxplot)
Hello all:
Is there a way to detect in R if a dataset is normally distributed or skewed without graphically seeing it? The reason I want to be able to do this is because I have developed and application with Visual Basic where Word,Access and Excel "talk" to each other and I want to integrate R to this application to estimate confidence intervals on fish sizes (mm). I basically want to
2013 Feb 13
2
e1071::skewness and psych::skew return NaN
Hello everyone,
Does anyone know what would cause the skewness() function (from
e1071), as well as skew() from psych, to return a value of NaN?
I have a vector of positively-skewed data
(https://docs.google.com/file/d/0B6-m45Jvl3ZmYzlHRVRHRURzbVk/edit?usp=sharing)
which these functions return a value for like normal:
> skewness( data ) # returns 1.400405
but when I instead give those
2017 Sep 25
2
build a SpatialLines object from a list
Hi all,I'm trying to build a SpatialLines object from a list that contains 124 river segments. Each segment in the list contains the x,y coordinates. I'm using the following code to create the SpatialLines object, but it just retrieves one segment. Any suggestions?
test.func = function(x){
??? for (i in 1:length(x)) {??????? tt[[i]] <- x[i]; tt[[i]]? = Line(tt[[i]]); tt[[i]]? =
2009 Mar 18
2
Xen WiFi Networks
Does xen virtualize wireless networks, and if not, why not? What is so difficult about it?
Regards!
Fasiha Ashraf
Unlimited freedom, unlimited storage. Get it now, on http://help.yahoo.com/l/in/yahoo/mail/yahoomail/tools/tools-08.html/
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2009 Sep 04
3
bridge throughput problem
I have set-up xen on my Intel quad core server. Now running different experiment to measure network throughput in virtualized environment. these are some of the results:
Netperf-4.5 results for inter-domain communication.
Sr.No. Client Server Time(sec) Throughput(Mbps)
1 Guest-1 Dom0
2007 Apr 09
1
Re: asterisk-users Digest, Vol 33, Issue 35
We i have settup it like this it giveme caller id agent id and date-time on
gsm file but i want them to be in folder on every day basis datewise.
exten =>
_1NXXNXXXXXX,2,Set(CALLFILENAME=${ACCOUNTCODE}-${EXTEN}-${TIMESTAMP})
exten => _1NXXNXXXXXX,3,Monitor(gsm,/rec/asterisk/apr07/${CALLFILENAME},mb)
Any Idea ?
Faisal
> ------------------------------
>
> Message: 16
>
2003 Apr 08
2
PXE stack on a floppy
Hi,
The link given in your http://syslinux.zytor.com/pxe.php#config page
points to the
http://www.argontechnology.ca/rbfg/index.shtml
site. This site talks only of Win2k and .Net server. There is no mention
of GNU/Linux. Is it possible to use rbfg.exe to create a pxelinux
bootable stack on a floppy. If so how ?
Rom-O-Matic has a pxe loadable ROM image. Is there a way to use this to