Displaying 20 results from an estimated 3000 matches similar to: "Coefficient of skewness"
2008 Jul 24
4
Is there an equivalent * operator?
Hi all,
Is there an equivalent to the general * operator in R, where * can
represent any character?
I have a dataset, one column being date, date ranging between
April-September, 97-06. I would like to be able to acquire the data for
a specific month, say September, so that I can take average temperatures
for the month, etc. I thought I would be able to do something like
data.s1 <-
2008 Sep 23
3
Generating series of distributions with the same skewness and different kurtosis or with same kurtosis and different skewness?
Dear R users,
I hope to explain the concepts of skewness and kurtosis by generating
series of distributions with same skewness and different kurtosis or with
same kurtosis and different skewness, but it seems that i cannot find the
right functions.
I have searched the mailing list, but no answers were found.
Is it possible to do that in R? Which function could be used?
Thanks a lot.
--
2008 Sep 08
3
Saving functions
Hi,
Appologies for the simple nature of this question, I am unable to find
the answer in manuals (EG and introduciton to R).
I have written a function in a text editor and saved it with an .R
extension. It is saved in my working directory. How can I run it, do I
need to use source? If so, how do I supply the arguments to the
function? Or does it need to be saved in a particular directory?
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
2008 Aug 18
2
Using lag
Dear all,
I am having difficulties using the seemingly-simple function lag.
I have a dataframe with several weather variables (maxitemp,
windspeed, rainfall etc), and the response variable (admissions). The
dataset is fairly large (1530 observations). I simply want to model the
response against a lag of a couple of the explanatory variables, say
maxitemp and rainfall. I would like to look at
2008 Jul 22
4
Opening files from R terminal - appologies
Dear all,
I appologise for cluttering up the list with such a basic question,
however I have been unable to find the answer I want (possibly through
my poor usage of the R help system).
As I am visually impaired and using assistive technology, I think I
would prefer to use R from the terminal mode, i.e. by running rterm.exe
found in the bin directory.
I have managed to set my working
2005 Jan 17
3
Skewness test
Hi,
is there a test for the H0 skewness=0 (or with skewness as test
statistic and normality as H0) implemented in R?
Thank you,
Christian
***********************************************************************
Christian Hennig
Fachbereich Mathematik-SPST/ZMS, Universitaet Hamburg
hennig at math.uni-hamburg.de, http://www.math.uni-hamburg.de/home/hennig/
2004 Oct 27
2
Skewness and Kurtosis
Hi,
in which R-package I could find skewness and kurtosis
measures for a distribution?
I built some functions:
gamma1<-function(x)
{
m=mean(x)
n=length(x)
s=sqrt(var(x))
m3=sum((x-m)^3)/n
g1=m3/(s^3)
return(g1)
}
skewness<-function(x)
{
m=mean(x)
me=median(x)
s=sqrt(var(x))
sk=(m-me)/s
return(sk)
}
bowley<-function(x)
{
q<-as.vector(quantile(x,prob=c(.25,.50,.75)))
2008 Jul 24
4
Just 2 more questions - for now!
Hi all,
Thanks for the help with my previous post.
I have just two more questions for the minute.
I think I said in a previous post that I like to use the terminal,
i.e. run rterm.exe. On exiting the terminal, I am asked if I want to
save the workspace. If I hit y (yes), the workspace is just saved as
.rdata in my working directory, does anyone know how I can name it
directly from the
2008 Sep 05
1
Orthogonalization algorithms
Hi,
I have eight vectors that I would like to orthogonalize preferably
using R. The vectors are of considerable length, however due to their
nature I know they satisfy the conditions needed to apply the
Gram-Schmidt algorithm. Before I embark on some R coding, I wanted to
check that there is no facility / function already around that computes
the orthogonalized set of vectors? I have performed
2004 Feb 09
2
moments, skewness, kurtosis
I checked the help and the mailing list archives, but I can
find no mention of a routine that calculates higher
moments like skewness and kurtosis. Of course, these
are easy enough to write myself, but I was thinking
that they MUST be in here. Am I wrong?
Thanks.
-Frank
2008 Aug 21
4
Very confused with class
Hi all,
I am very confused with class.
I am looking at some weather data which I want to use as explanatory
variables in an lm. R has treated these variables as factors (i.e. with
different levels), whereas I want them treated as discretely measured
continuous variables. So I need to reassign the class of these
variables, right?
Indeed, doing
class(southwest$pressure)
(pressure being air
2011 Oct 25
1
alternative option in skewness and kurtosis tests?
I have a question about the D'Agostino skewness test and the Anscombe-Glynn
kurtosis test.
agostino.test(x, alternative = c("two.sided", "less", "greater"))
anscombe.test(x, alternative = c("two.sided", "less", "greater"))
The option "alternative" in those two functions seems to be the null
hypothesis. In the output, the
2006 Apr 10
2
how to figure out "skewness"
I think it is simply, but I cannot find the method to figure out "skewness".
Thanks!
[[alternative HTML version deleted]]
2008 Aug 28
1
Renaming objects
Hi,
Is there any quick and easy way to rename a number of objects, without
having to rename each one individually and then remove the old one? And
if so, is there anything I can do to adjust the associated comments
accordingly?
Thanks for any help,
Robin Williams
Met Office summer intern - Health Forecasting
robin.williams@metoffice.gov.uk
[[alternative HTML version deleted]]
2005 May 23
3
skewness and kurtosis in e1071 correct?
I wonder whether the functions for skewness and kurtosis in the e1071
package are based on correct formulas.
The functions in the package e1071 are:
# --------------------------------------------
skewness <- function (x, na.rm = FALSE)
{
if (na.rm)
x <- x[!is.na(x)]
sum((x - mean(x))^3)/(length(x) * sd(x)^3)
}
# --------------------------------------------
and
#
2001 Dec 10
2
distributions w. skewness & kurtosis
Is there some reasonable way to generate random data from a
distribution that has some degree of skewness and/or kurtosis, but
would otherwise be normal?
thanks,
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1999 Jul 28
1
skewness, kurtosis
Dear R-Users and Developpers,
Currently R does not include functions to compute the skewness and
kurtosis. I programmed it myself in the following way, but probably
*real* programmers/statisticians can do that better:
mykurtosis <- function(x) {
m4 <- mean((x-mean(x))^4)
kurt <- m4/(sd(x)^4)-3
kurt
}
myskewness <- function(x) {
m3 <- mean((x-mean(x))^3)
skew <-
2001 Sep 28
1
Generate rand. data with zero skewness and some kurtosis
Dear all,
Right now, I'm doing research about outlier in statistical data
(univariate and multivariate) and I want to simulate its behavior. My
problem is :
How to generate random data from distribution with zero skewness and
some kurtosis values in R ?
A. Kudus
=====================
Dept. of Statistics
Bandung Islamic University
I n d o n e s i a
==========================
2006 Sep 08
1
Computing skewness and kurtosis with the moments package
Hi,
I'm a newcomer to R, having previously used SPSS. One problem I have
run into is computing kurtosis. A test dataset is here:
http://www.whinlatter.ukfsn.org/2401.dat
> library(moments)
> data <- read.table("2401.dat", header=T)
> attach(data)
> loglen <- log10(Length)
With SPSS, I get
Skewness -0.320
Kurtosis -1.138
With R:
> skewness(loglen)
[1]