Displaying 20 results from an estimated 2000 matches similar to: "question about shapiro.test()"
2007 Mar 18
2
ticks labels and R
Hi,
I have plot a graphics by next way:
par(mar=c(5,5,1,1), font.axis=3, ps=14, xaxs="i", yaxs="i", lab=c(18,18,7),
font
.lab=3);
plot(l, b, type="n", xlim=c(0,360), ylim=c(-90,90), xlab="l, deg", ylab="b,
deg");
points(l, b, cex=vel/60, col=1, pch=21);
On this plot I have axis x (denoted by l) ranged in [0,360] with labeling step
20. But I
2010 Apr 16
2
managing data and removing lines
Hi,
I am very new to R and I've been trying to work through the R book to gain a
better idea of the code (which is also completely new to me).
Initially I imputed my data from a text file and that seemed to work ok, but
I'm trying to examine linear relationships between gdist and gair, gdist and
gsub, m6dist and m6air, etc.
This didn't work and I think it might have something to do
2009 Aug 13
1
R code to reproduce (while studying) Bates & Watts 1988
Hi R users,
I'm here trying to understand correlated residuals in nonlinear estimation.
I'm reading/studying the book Bates, D. M. and D. G. Watts, (1988),
/Nonlinear regression analysis and its applications/, Wiley, NY. pages
92-94, trying to reproduce the figures and to find out the code in R to
perform the necessary calculations.
I also consulted Pinheiro and Bates, but without
2008 Jul 12
5
shapiro wilk normality test
Hi everybody,
somehow i dont get the shapiro wilk test for normality. i just can?t
find what the H0 is .
i tried :
shapiro.test(rnorm(5000))
Shapiro-Wilk normality test
data: rnorm(5000)
W = 0.9997, p-value = 0.6205
If normality is the H0, the test says it?s probably not normal, doesn
?t it ?
5000 is the biggest n allowed by the test...
are there any other test ? ( i know qqnorm
2015 May 14
3
comportamiento de data.table al hacer calculos por grupos
Estimada comunidad tengo un problema del que no encuentro datos que me
ayuden mucho en la web.
Estoy haciendo calculos por grupos con data,table. Tengo un archivo
(zp.res) con tres columnas que clasifican los datos (sol, con, dia) y
una columna de datos numericos (media), de la siguiente forma:
sol con dia media
1: con 0 1 -22.6
2: con 0 1 -36.6
3: con 0 1 -35.6
y
2013 Jul 23
0
Function apply
Hi,
Try:
set.seed(25)
X<- matrix(sample(1:50,3*140,replace=TRUE),nrow=140)
#either
res1<-do.call(rbind,lapply(split(as.data.frame(X),((seq_len(nrow(X))-1)%/%10)+1),function(x) apply(x,2,mean)))
#or
?res2<-t(sapply(split(as.data.frame(X),((seq_len(nrow(X))-1)%/%10)+1),colMeans))
?identical(res1,res2)
#[1] TRUE
#orlibrary(itertools)
it<-ihasNext(isplitRows(X,chunkSize=10))
2004 Nov 17
0
log-normal distribution and shapiro test
Hello:
Yes I know that sort of questions comes up quite often. But with all due
respect I din't find how to perform what I want. I am searching archives
and bowsing manuals but it isn't there, though, it is a ridiculous
simple task for the experienced R user.
I have data and can do the following with them:
==
hist(y, prob=TRUE)
lines(density(y,bw=0.03)
==
The result actually is a
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
2009 Sep 14
1
ggplot2 graphing multiple lines of data
Some day I may figure out how ggplot2 works.
I am trying to plot 5 columns of data on a graph (similar to a simple matplot)
===========================================================================
library(ggplot2)
bmi <- structure(list(pct = 2:21, P10 = c(14.6, 14.5, 14.2, 13.9, 13.7,
13.7, 13.9, 14.2, 14.5, 14.8, 15.3, 15.9, 16.6, 17.2, 17.8, 18.1,
18.3, 18.4, 18.5, 18.6), P25 =
2007 Jun 29
1
Shapiro Test P Value Incorrect? (PR#9768)
Full_Name: Jason Polak
Version: R version 2.5.0 (2007-04-23)
OS: Xubuntu 7.04
Submission from: (NULL) (137.122.144.35)
Dear R group,
I have noticed a strange anomaly with the shapiro.test() function. Unfortunately
I do not know how to calculate the shapiro test P values manually so I don't
know if this is an actual bug.
So, to produce the results, run the following code:
pvalues = 0;
for
2003 Feb 10
2
shapiro.test
Hi
The shapiro.test function outputs a value of the W statistic, which
should be 1 if the distribution is normal, and a p-value for the test
(as the documentation states).
I'm a bit confused with some results. I'm getting a W=0.9977 and a
p-value=0.1889.
I was expecting that a W of 0.9977 would tell me that the distribution
is normal so p-value should be small ...
What am I missing ?
2012 May 02
2
output Shapiro-Wild results to a table
Hello,
I have applied the Shapiro test to a matrix with 26.925 rows of data using the following
F1.norm<-apply(F1.n.mat,1,shapiro.test)
I would now like to view and export a table of the p and W values from the Shapiro test, but I am not sure how to approach this.
I have tried the following with errors.
> write.table(x=F1.norm,file="I:/R_Work/F1/Shapiro.csv",
2008 Apr 26
0
Consistency of m-shapiro.test
Hello all,
I tried several experiments with the mshapiro.test package in R and compared
it with the energy package to test for multivariate normality and find that
the mshapiro.test is not consistent which is a bit concerning and has
suspicious behavior. On the other hand the energy test seems to be a more
appropriate test for testing multivariate normality in any dimension. I
looked for the
2009 Feb 06
1
beanplot, Error in shapiro.test(x)
Dear all,
I am trying to create beanplots from a dataset for which boxplot works fine.
(MACOS, R 2.8.1 GUI 1.27 Tiger build 32-bit (5301))
I am getting the following error message:
Error in shapiro.test(x) : sample size must be between 3 and 5000
I am not even sure why the shapiro.test is being used, but is there any
workaround ?
Thanks !
Markus
[[alternative HTML version deleted]]
2000 Sep 25
1
Interpretation of Shapiro-Wilk
Can anybody tell me the exact meaning of the $statistic and $p.value
calculated by shapiro.test? Unfortunately it is not covered in my few
text books, and I cannot find the explanation in the R documentatiom or
on-line.
If I have a test statistic, T, which is Normally distributed with mean=m
and sd=s under the null hypothesis, then I can convert T to a p-value
(one-sided) using:
p <- pnorm(T,
2005 Nov 18
1
help on ks.test and shapiro.test
I have three files of data which are available at http://zhangw.com/
R/, varied at the number of data. I tried to use R to analyze using
shapiro.test, ks.test, and t.test. t.test ran as expected, however,
when I run shapiro.test and ks.test commands, error message always
occurred. Error message for
shapiro.test is
"Error in "[.data.frame"(x, complete.cases(x)) :
undefined
2007 Sep 29
1
Shapiro-Welch W value interpretation
Hello,
I have tested a distribution for normality using the Shapiro-Welch
statistic. The result of this is the following:
Shapiro-Wilk normality test
data: mydata
W = 0.9989, p-value = 0.8791
I know that the p-value > 0.05 (for my purposes) means that the data
IS normally distributed but what I am not sure is with the W value,
what values tell me that the data is normally
2009 Jun 22
2
Shapiro.test on data frame
Hi, I need help to perform a Shapiro.test on a data frame, I know that
this test works only with vector but I guess there most be a way to
permor it on a data frame instead of vactor by vector (i.e. I've got 40
variables to analyze and its kinda annoying to do it one by one)
Thanks to anyone that can help me.
Gonzalo Quiroga
2008 Oct 09
1
interpreting Shapiro-Wilks test result
Hi all,
I am newbie in using R software and also doing statistical test. I want to know if my data in in normal distribution. I have 2 groups of data and I did calculate Shapiro Wilks using R software. Here is the results:
Group 1: W = 0.9206, p-value = 0.01683
Group 2: W = 0.9626, p-value = 0.4694
I am not quite sure what default confidence level (CF) is used in calculating Shapiro Wilks.
1999 Nov 04
1
shapiro wilk
I'm pretty new to R and are trying to do some reliable normality
testing... but, can't find the Shapiro Wilk test in R Does some
experienced user have such a function that will be wanting to share with
me? Or there is maybe some other way to get hte Shapiro Wilk test
done... I'll appreciate any hint on this,
Thanks
--
***********************
Horacio Samaniego
Dep. Ecologia
P.