Displaying 20 results from an estimated 1000 matches similar to: "t-test behavior given that the null hypothesis is true"
2013 Jan 09
0
[solved] t-test behavior given that the null hypothesis is true
Hi Ted,
yes this was the problem. Thank you very much.
best
idaios
On Wed, Jan 9, 2013 at 4:51 PM, Ted Harding <Ted.Harding@wlandres.net>wrote:
> Ah! You have aqssigned a parameter "equal.var=TRUE", and "equal.var"
> is not a listed paramater for t.test() -- see ?t.test :
>
> t.test(x, y = NULL,
> alternative = c("two.sided",
2013 May 16
2
R looping help
Hey I'm not really sure what I should put on here, but I am having trouble
with my R code. I am trying to get the p-values, R^2s etc for a number of
different groups of variables that are all in one dataset.
This is the code:
#Stand counter
st<-1
#Collections
stands<-numeric(67)
slopes<-numeric(67)
intercepts<-numeric(67)
mses<-numeric(67)
rsquares<-numeric(67)
2010 Nov 30
2
Adding noise
Hello,
I have some discrete pvalues and I would like to sort them. Then add random
noise so that they are ordered the same way as the original pvalues. Off
course I don't want any pvalues less than 0 or greater than 1. Any ideas on
how to do this in R?
--
Thanks,
Jim.
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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
2011 Jul 04
2
clustering based on most significant pvalues does not separate the groups!
Hi all,
I have some microarray data on 40 samples that fall into two groups. I have
a value for 480k probes for each of those samples. I performed a t test
(rowttests) on each row(giving the indices of the columns for each group)
then used p.adjust() to adjust the pvalues for the number of tests
performed. I then selected only the probes with adj-p.value<=0.05. I end up
with roughly 2000
2008 Jan 19
1
How do we get two-tailed p-values for rlm?
How do we get 2-tailed p-values for the rlm summary?
I'm using the following:
> fit <- rlm(oatRT ~ oatoacData$erp, psi=psi.bisquare, maxit=100,
na.action='na.omit')
> fitsum <- summary(fit, cor=F)
> print(fitsum)
Call: rlm(formula = oatRT ~ oatoacData$erp, psi = psi.bisquare, maxit = 100,
na.action = "na.omit")
Residuals:
Min 1Q Median
2017 Jun 29
0
Help : glm p-values for a factor predictor
It might help if you provided the code you used. It's possible that
you didn't use direction="backward" in stepAIC(). Or if you did, it
was still running, so whatever else you try will still be slow. The
statement "R provides only the pvalues for each level" is wrong: look
at the anova() function.
Bob
On 29 June 2017 at 11:13, Beno?t PELE <benoit.pele at
2017 Jun 29
3
Help : glm p-values for a factor predictor
Hello,
i am a newby on R and i am trying to make a backward selection on a
binomial-logit glm on a large dataset (69000 lines for 145 predictors).
After 3 days working, the stepAIC function did not terminate. I do not
know if that is normal but i would like to try computing a "homemade"
backward with a repeated glm ; at each step, the predictor with the max
pvalue would be
2020 Oct 18
1
Resultado de la consola como un tibble
Hola,
Bueno, puedes hacer el cálculo de una forma mucho más compacta y rápida.
Esta forma es especialmente recomendable cuando tienes muchas columnas y
muchas filas.
> library(data.table)
> myDT <- as.data.table(mtcars)
> myDTlong <- melt(myDT, measure.vars=1:ncol(myDT))
> myDTlong[ , list(p_value = shapiro.test(value)$p.value, v_stat =
shapiro.test(value)$statistic) , by
2005 Jul 26
1
Help on T test
ok I created a matrix C with
A B C A1 B1 C1
..................................
.................................
the columns contain the gene expression values..
I ran the following t.test:
apply(C, 1, function(x) t.test( x[1:3], x[4,6] )$p.value )
which outputs out 16063 pvalues (the number of rows)
I just want to output 3 pvalues showing if A's column is different from A1
2007 Aug 24
1
chi-square statistics
I'm wondering if R has functions to return pvalues with given x-squares and
df. I googled for it but couldn't seem to find one. Appreciate any helps
here.
An example: df=4, x<- c(33.69, 32.96, 30.90) which are the statistic for
chi-square, I'd like to get the corresponding pvalues for each values in x.
Thanks.
-Karen
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2011 Feb 26
1
Pulling p values
Hi folks,
I'm doing ANOVA with multiple comparisons. I've used both the TukeyHSD function and the multcomp procedure. In both cases, I get some tantalizing results such as this...
e = aov(lm(d.all[,(n+4)] ~ d.all[,4])
TukeyHSD(e)
Tukey multiple comparisons of means
95% family-wise confidence level
Fit: aov(formula = lm(d.all[, (n + 4)] ~ d.all[, 4], contrast = C))
$`d.all[,
2011 Sep 19
1
regression summary results pvalues and coefficients into a excel
Hi All,
I have run many regression analyses (14000 +) and want to collect the
coefficients and pvalues into an excel file. I can get the statements below
to work up to step 4. I can printout the regressionresults (sample output
below).
So my hope is to run something like step 5 and 6 and put the pvalues (and
then coefficients) into an excel file. Can anyone suggest what I am doing
wrong or a
2003 Sep 05
2
stack overflow
Hello,
I am trying to do an ANOVA on a microarray data set consisting of
22690 elements. The ANOVA is fine, but when I try to put the data in
a frame in order to exporting it, I get a stack overflow. I have
found documentation on dynamic memory in R, but not on how to increase
the stack size. The code I'm using is below. If anyone has any
suggestions for a workaround here, I'd
2010 Oct 22
2
Bayesian constrained regression method?
Hello everyone,
I am trying to estimate the parameter b.
I have Y and X1 which I know and they are both random. However, I also have
X2 which I don't know and is also random. I want to estimat b from the
model:
Y = b*X1 + ( 1 - b ) * X2
Can anyone offer some suggestions. The values of Y and X1 are both pvalues
so they are constrained in (0,1).
--
Thanks,
Jim.
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2007 Mar 18
1
multcomp
I used the multcomp package sometime back for doing multiple
comparisons. I see that it has been updated and the methods like simint
are no longer supported. When I run the program it prompts to me to use
glht. How do I get the lower and upper conf int and the pValues using
glht? Does anyone have an example?
Thanks ../Murli
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2009 Jun 15
1
multcomp: contrasts for count data
Hi,
I would like to derive p-values for pair-wise comparison (Tukey's) of
effects when the response is a count.
I am trying a test case where y ~ Po( lambda(x) ). x has three
levels : A, B and C with lambda(x) = 10, 20 and 20 respectively.
Hence, p-values for the contrast C - B should distribute uniformally.
I have implemented this test case as below but do not get uniform
2008 Nov 26
2
Very slow: using double apply and cor.test to compute correlation p.values for 2 matrices
My two matrices are roughly the sizes of m1 and m2. I tried using two apply and cor.test to compute the correlation p.values. More than an hour, and the codes are still running. Please help to make it more efficient.
m1 <- matrix(rnorm(100000), ncol=100)
m2 <- matrix(rnorm(10000000), ncol=100)
cor.pvalues <- apply(m1, 1, function(x) { apply(m2, 1, function(y) { cor.test(x,y)$p.value
2009 Aug 28
1
extracting pvalues from ttest
Hello list,
I have a similar issue as this post
http://tolstoy.newcastle.edu.au/R/e6/help/09/04/11438.html#options2 and I
used the suggestion provided by Jorge with modifications to my data
do.call(c,lapply(your_list_with_the_t_tests,function(x) x$p.value))
but I am getting the following error after excuting the code
B<-by(eo,eo$PlateID, function(.sub) t.test(mcp1~Self_T1D,data=.sub,
2008 Jan 02
1
extracting pvalue from ANOVA with repeated measures
I made an ANOVA with repeated mesures
(aov(Mesure~Distance*Genre*Correct+Error(Sujet/(Distance*Genre*Correct)),
data)) and I would like to extract the pvalues.
The output is:
-----------------------------------------------------------
Error: Sujet
Df Sum Sq Mean Sq F value Pr(>F)
Residuals 21 97.082 4.623
Error: Sujet:Distance
Df Sum Sq Mean Sq F value Pr(>F)
Distance