Displaying 20 results from an estimated 2000 matches similar to: "Skewness and Kurtosis"
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 Nov 17
1
R: log-normal distribution and shapiro test
Hi,
from what you're writing:
"The logaritmic transformation
"shapiro.test(log10(y))" says: W=0.9773, p-value=
2.512e-05." it seems the log-values are not
distributed normally and so original data are not
distributed like a log-normal: the p-value is
extremally small!
Other tests for normality are available in package:
nortest
compare the log-transformation of your ecdf
2004 Oct 22
3
Convert a list in a dataframe
Hi,
I've a list containing parameters (intercepts &
coefficients) of 12 regressions fitted
> coeff
[[1]]
(Intercept) anno
-427017.1740 217.0588
[[2]]
(Intercept) anno
-39625.82146 21.78025
.....
[[12]]
(Intercept) anno
257605.0343 -129.7646
I want create a data frame with two columns (intercept
and anno)using data in these list.
Any help
2004 Jul 21
2
Testing autocorrelation & heteroskedasticity of residuals in ts
Hi,
I'm dealing with time series. I usually use stl() to
estimate trend, stagionality and residuals. I test for
normality of residuals using shapiro.test(), but I
can't test for autocorrelation and heteroskedasticity.
Is there a way to perform Durbin-Watson test and
Breusch-Pagan test (or other simalar tests) for time
series?
I find dwtest() and bptest() in the package lmtest,
but it
2005 Jan 13
2
multivariate diagnostics
Hi, there.
I have two questions about the diagnostics in multivarite statistics.
1. Is there any diagnostics tool to check if a multivariate sample is from
multivariate normal distribution? If there is one, is there any function
doing it in R?
2. Is there any function of testing if two multivariate distribution are
same, i.e. the multivariate extension of Kolomogrov-Smirnov test?
Thanks for
2004 Nov 10
2
fSeries
Good morning everyone,
I use for the first time the package fSeries and i try to run the example
given by Diethelm Würtz. But when i run its example which is the following
#
# Example:
# Model a GARCH time series process
#
# Description:
# PART I: Estimate GARCH models of the following type ARCH(2)
# and GARCH(1,1) with normal conditional distribution functions.
# PART II: Simulate
2005 Dec 01
2
about comparison of KURTOSIS in package: moments and fBasics
Hello
I do not know very much about statistics (and English language too :-( ),
then I come in search of a clarification (explanation):
I found two distinct results on KURTOSIS and
I do not know which of them is the correct one.
Any aid will be welcome!
klebyn
################ CODE
rnorm(1000) -> x
library(moments)
kurtosis(x)
skewness(x)
detach("package:moments")
2004 Aug 09
2
Using R "boxplot" function in Excel
Hi, I have downloaded the "R-Com and I was able to run "Interactive Graphics
Demo 2" in excel. However, I couldn't create my own boxplot. Whenever I
tried to run any code, it always say" Error in loading DLL", even
"=rput(A1,A2:A20)". Any idea about what's going wrong? A detailed
explaination about how to use R-Excel tool would be greatly appreciated.
2004 Oct 20
2
R & Graphs
Dear R-users,
I'm finding for a R-package concerning graphs. Is
there some kind of that package? I've a set of
correlation coeffients between several variable and I
wish to built a graph to link variables correlated.
Many thanks.
Best,
Vito
=====
Diventare costruttori di soluzioni
"The business of the statistician is to catalyze
the scientific learning process."
George
2004 Nov 15
1
R: how can draw probability density plot?
I hope this example could help you
best
vito
> x<-seq(-3.5,3.5,0.1)
> x
[1] -3.5 -3.4 -3.3 -3.2 -3.1 -3.0 -2.9 -2.8 -2.7 -2.6
-2.5 -2.4 -2.3 -2.2 -2.1
[16] -2.0 -1.9 -1.8 -1.7 -1.6 -1.5 -1.4 -1.3 -1.2 -1.1
-1.0 -0.9 -0.8 -0.7 -0.6
[31] -0.5 -0.4 -0.3 -0.2 -0.1 0.0 0.1 0.2 0.3 0.4
0.5 0.6 0.7 0.8 0.9
[46] 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9
2.0 2.1 2.2 2.3
2004 Jul 07
7
Importing an Excel file
Hello, R users,
I am a very beginner of R and tried read.csv to import an excel file after
saving an excel file as csv. But it added alternating rows of fictitious NA
values after row number 16. When I applied read.delim, there were trailing
several commas at the end of each row after row number 16 instead of NA
values. Appreciate your help.
Kyong
[[alternative HTML version deleted]]
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.
--
2004 Nov 10
1
Loading some function at R startup
Dear R-users,
I've built these functions usefell for me to
import/export data from/to Excel:
importa.da.excel<-function(){read.delim2("clipboard",
dec=",")
## questa funzione consente di importare dati da Excel
in R
## selezionare in Excel le celle che contengono i
dati,
## compresi in nomi delle colonne
## Autore: Vito Ricci email:vito_ricci at yahoo.com
## Data di
2004 Jul 07
1
Daily time series
Hi,
I'm dealing with time series with 1 observaton for day
(data sampled daily). I will create a ts object using
that time series and the function ts().
In ts() help is written:
The value of argument 'frequency' is used when the
series is sampled an integral number of times in each
unit time interval. For example, one could use a value
of '7' for 'frequency' when
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
2004 Aug 12
4
Help with generating data from a 'not quite' Normal distriburtion
I would be very grateful for any help from members of this list for what
might be a simple problem...
We are trying to simulate the behaviour of a clinical measurement in a
series of computer experiments. This is simple enough to do in R if we
assume the measurements to be Gaussian, but their empirical distribution
has a much higher peak at the mean and the distribution has much longer
tails.
2004 Nov 12
4
Mode in case of discrete or categorial data
Thanking John for his suggestion I build this function
which get the mode of both categorial and discrete
data.
Mode<-function(x){t<-table(x)
if (is.numeric(x)) as.numeric(names(t)[t == max(t)])
else (names(t)[t == max(t)])
}
Any other improvement and suggestion will welcome.
Best
Vito
> s
[1] 1 1 6 1 1 7 6 5 6 2 1 4 5 6 6 7 3 5 4 1 7 3 7 3 3
7 7 2 1 4 4 2 7 7 6 6 1 2
[39] 5 1 7 7
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
#
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
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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