Displaying 20 results from an estimated 3000 matches similar to: "Calculation of Central Moments"
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")
2008 Nov 06
4
mean computation for external data
I have an external data (.txt) for
annual peak flood. The first column is the year, second column is the
observation date, and the last is the observed discharge. My task is to
calculate the mean, skewness and kurtosis of the said data. I was advised to use
read.table() to read the entire data. Please help me on how to perform the
required computation. I am obviously a new user of this statistical
2008 Jul 09
5
Summary Stats (not summary(x))
I'm looking for a function that lists a few summary stats for a column (or
row) of data. I'm aware of summary(x), but that does not give me what I'm
looking for.
I'm actually looking for something that is very similar to the descriptive
statistics tool in excel; i.e. Mean, Std. Error, Std. Deviation, Kurtosis.
I'm positive that I came across a function that did this (possibly
2009 Mar 18
2
Three Parameter FRECHET Distribution
Dear R Helpers
Which package is available for estimatine the parameters of three parameter FRECHET distribution. Also, how to generate the random numbers for Frechet using these three estimated parameters.
Thanking in advance
Maithili
2009 Aug 27
2
Comparing and adding two data series
Dear R helpers
I have two series A and B as given below -
A <- c(2, 2, 1, 3, 7, 3, 3, 1, 14, 7, 31)
B <- c(0.0728,0.9538,4.0140,0.0020,2.5593,0.1620,2.513,0.3798, .0033,0.2282, 0.1614)
I need to calculate the total in dataset B corresponding to the numbers in dataset A i.e. for no 1 in A, I need the total as 4.0140+0.3798 (as 1 is repeated twice)
for no 2, I need the total as
2009 Mar 16
1
Fw: Fitting GUMBEL Distribution - CDF function and P P Plot
Dera R Helpers,
I am re-posting my query.
Please guide me.
Maithili
--- On Fri, 3/13/09, Maithili Shiva <maithili_shiva at yahoo.com> wrote:
I am trying to fit the Gumbel distribution to a data. I am
using lmom package. I am getting problem in Cumulative
Distribution Function of Gumbel distribution as I am getting
it as a series of 0's and 1's thereby affecting the
P P
2009 Dec 04
2
writing 'output.csv' file
Dear R helpers
Suppose
M <- c(1:10) # length(M) = 10
N <- c(25:50) # length(N) = 26
I wish to have an outut file giving M and N. So I have tried
write.csv(data.frame(M, N), 'output.csv', row.names = FALSE)
but I get the following error message
Error in data.frame(M, N) :
arguments imply differing number of rows: 10, 26
How do I modify my write.csv
2009 Feb 06
2
Matrix Multiplication
Hi R helpers,
I have two matrices A and B of the order (4 * 5) and (5 * 3) respectively. How to multiply these two matrices to obtain resultant matrix of the order (4 * 3).
Thanks in advance
With regards
Maithili
2008 Oct 07
3
How to validate model?
Hi!
I am working on scorecard model and I have arrived at the regression equation. I have used logistic regression using R.
My question is how do I validate this model? I do have hold out sample of 5000 customers.
Please guide me. Problem is I had never used Logistic regression earlier neither I am used to credit scoring models.
Thanks in advance
Maithili
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
2009 Aug 27
2
Fw: PROBLEM - - COMPARING AND COMBINING two DATASETS
Dear Sirs,
?
At the outset I sincerely apologize for reproducing my query to you. I also thank all of you for the solution you had provided. It has worked on the actual data I am working with.
?
However, there is this peculiar problem which I had realized only after I had obtained my results.
?
e.g. in the example I had attached
?
A?<-?c(2, 2, 1, 3, 7, 3, 3, 1,?14, 7, 31)
B?<-
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]
2009 Dec 23
2
Mean, median and other moments
Hi!
Suppose I have a dataset as follows
pd = c(10,7,10,11,7,11,7,6,8,3,12,7,7,10,10)
I wish to calculate the mean, standard deviation, median, skewness and kurtosis i.e. regular standard statistical measures.
average = mean(pd)
stdev = sd(pd)
median = median(pd)
skew = skewness(pd)
kurt = kurtosis(pd)
Q. No (1)
How do I get these at a stretch using some R package? I came across
2009 Jan 08
2
VaR-Monte carlo Simulation, Historic simulation, Variance-Covariance Simulation
Dear R helpers
Suppose I have a portfolio of securities with exposure to Equity, Bonds and Forex (say $ 1000000 each).
Is there any fucntion in R that will help me calculate Value at Risk (VaR) using Monte carlo Simulation , Historic simulation and Variance - Covariance Simulation.
With regards
Maithili
2009 Mar 05
2
Fast Fourier Transform w.r.t. CreditRisk+
Dear R Helpers,
Is there any literaure available (including R code) on Fast Fourier Transform being used in CreditRisk+? I need to learn how to apply the Fast Fourier Transform. I agree I am too vaue in my question and sincerely apologize for the same, but I am not able to understand as to where do I start for this particular assignment. I tried to search google for CRAN and Fast Fourier
2009 Dec 24
3
An unprofessional message
Dear R helpers,
I understand that this is absolutely unprofessional on my part and this group doesn't entertain such things. I have been associted with this group since last 1 and half years and have been immensely benefited by the noble service rendred by many R helpers.
So I take this opportunity to thank all of you and wish you all
"MERRY CHRISTMAS".
I sincerely apologize
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)))
2007 Feb 22
1
Diagnostic Tests: Jarque-Bera Test / RAMSEY
Hello R-Users,
The following questions are not R-technical, but more of general statistical
nature.
1. NORMALITY
I built a normal linear regression model and now I want to check for the
residual normality assumption. If I check the distribution graphically and
look at the descriptive characteristics (skewness and kurtosis are below 1),
I would confirm that the residuals are normally
2008 Dec 18
1
Random Number Generation using (Generalized) Extreme Value distribution and Pareto distribution
Hi R helpers,
Is there any function in R, which generates random numbers in case of
(1) Generalized Extreme Value distribution and
(2) Generalized PAreto distribution for the respective given set of parameters?
Regards
Maithili
2009 Jul 21
1
lmom - Estimating Normal Distribution Parameters using lmom package
Dear R helpers,
I have a data of 2102 observations (consisting of 0's also), to which I am trying to fit Normal distribution using "lmom" pacakage. If I use Excel, its easy to estimate the parameters of Normal distribution as simple mean and standard devaition. The results I get if I use teh excel are as
Parameters of Normal distribution :-
Mean = 22986.44 and standard