Displaying 20 results from an estimated 1000 matches similar to: "[solved] t-test behavior given that the null hypothesis is true"
2013 Jan 09
1
t-test behavior given that the null hypothesis is true
Dear all,
I observer a strange behavior of the pvalues of the t-test under the null
hypothesis. Specifically, I obtain 2 samples of 3 individuals each from a
normal distribution of mean 0 and variance 1. Then, I calculate the pvalue
using the t-test (var.equal=TRUE, samples are independent). When I make a
histogram of pvalues I see that consistently the bin of the smallest
pvalues has a lower
2011 Oct 23
0
FW: Re: symmetric matrix multiplication
Just to avoid possible confusion, let me correct a typo
(at step [2] in the example below). Apologies!
-----FW: <XFMail.111023084327.ted.harding at wlandres.net>-----
Date: Sun, 23 Oct 2011 08:43:27 +0100 (BST)
Sender: r-help-bounces at r-project.org
From: (Ted Harding) <ted.harding at wlandres.net>
To: r-help at r-project.org
Subject: Re: [R] symmetric matrix multiplication
On
2002 Nov 13
0
Welch versus Satterthwaith (PR#2111)
>>>>> "TL" == Thomas Lumley <tlumley@u.washington.edu>
>>>>> on Sun, 6 Oct 2002 09:19:27 -0700 (PDT) writes:
TL> On Sat, 5 Oct 2002 roxburg@kih.net wrote:
>> This is not a bug report but didn't see another way to
>> ask a question.
TL> Well, you could try the r-help or r-devel mailing lists
>> For
2013 Apr 25
2
Decomposing a List
Greetings!
For some reason I am not managing to work out how to do this
(in principle) simple task!
As a result of applying strsplit() to a vector of character strings,
I have a long list L (N elements), where each element is a vector
of two character strings, like:
L[1] = c("A1","B1")
L[2] = c("A2","B2")
L[3] = c("A3","B3")
2008 Mar 31
1
Compile dll in Windows XP
This is my first attempt to call a C function from R. I have installed Rtools,MinGW and Perl and I have included them in my system path. I am trying to compile a toy function that can be called in R but when I type "RCMD SHLIB foo.c" I receive the following message in my Command prompt:
making foo.d from foo.c
make: [foo.d] Error 255 (ignored)
cat: foo.d: No such file or directory
make:
2013 Mar 26
2
edit.data() read-only?
Greetings All.
The function edit.data() allows a convenient spreadsheet-like
view of a dataframe with too many rows/columns to fit on the
screen (especially when there are many columns). Very useful
when scanning through a dataset (row & column are conveniently
identified by the labels at the side and above).
However, there seens to be no option to set it "read-only" on
start-up,
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)
2012 Jul 10
2
RGB components of plot() colours
A quick question:
Is there anywhere a listing of the RGB components of the
named colours listed by colors()?
For example, where would I find the RGB for "orange1"
or "salmon"?
When I look at an EPS file from R where I have used
these colours, it seems that for:
"salmon":
0.9804 0.5020 0.4471 rgb
"orange1":
1 0.6471 0 rgb
However, this is a tedious way
2012 Feb 25
2
Finding name of variable supplied as function argument
Greetings All.
I want to do the following simple thing. I have defined
a function med3x3() such that, given vectors X,Y,
med3x3(X,Y) returns a 3x3 table where:
Row 1: X > median(X)
Row 2: X = median(X)
Row 3: X < median(X)
Col 1: Y < median(Y)
Col 2: Y = median(Y)
Col 3: Y > median(Y)
(with intersections of these conditions for the individual cells).
I can easily define fixed
2019 Jan 01
1
I can't find what's causing this warning?
This is also on Stack Overflow…
It’s odd, because sometimes it seems to wrk, and sometimes not???
error.log
[2019-01-01 13:08:31] INFO admin/admin_handle_request Bad or missing password on admin command request (command: stats.xml)
[2019-01-01 13:08:31] INFO admin/admin_handle_request Bad or missing password on admin command request (command: stats.xml)
[2019-01-01 13:08:31] INFO
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
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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2017 Nov 29
0
How to extract coefficients from sequential (type 1), ANOVAs using lmer and lme
(This time with the r-help in the recipients...)
Be careful when mixing lme4 and lmerTest together -- lmerTest extends
and changes the behavior of various lme4 functions.
>From the help page for lme4-anova (?lme4::anova.merMod)
> ?anova?: returns the sequential decomposition of the contributions
> of fixed-effects terms or, for multiple arguments, model
>
2010 Nov 13
1
Efficient marginal sums?
Hi Folks,
[This is not unrelated to the current "vector of vectors" thread,
but arises quite independently]
Say I have a function f(x,y) which computes a value for scalar
x and y; or, if either x=X or y=Y is a vector, a corresponding
vector of values f(X,y) or f(x,Y) (with the usual built-in
vectorisation of operations).
Now I have X=(x.1,x.2,...,x.m) and Y=(y.1,y.2,...,y.n).
I'm
2012 Oct 31
0
combined dependent pvalue
Dear All,
I am trying to combine dependent p-values in R. May you please help me with
this?
For independent pvalue combination, one of the popular way is fisher's
method which I found the R code here
(http://r.789695.n4.nabble.com/fisher-s-posthock-test-or-fisher-s-combination-test-td2195964.html#a2305025):
fisher.comb <- function (pvalues)
{
df=length(pvalues)
2013 Apr 25
0
fdrtool qvalues
Hi,
I've just started using R and fdrtool, and I'm not sure if the qvalues I'm receiving back are accurate. I performed fdrtool on pvalues obtained from a two way anova on proteomics data. So I have 266 data values (protein spots) for two factors (ft, vr, and the interaction) for each biological sample.
One of the two factors (vr) has a highly significant effect with 119 protein
2012 Jul 30
6
Turning off continuation prompt?
Greetings All.
My apologies for a question whose answer is probably
readily available somewhere (for some interpetation
of "somewhere") ...
Say I have just typed (from a sheet of paper) several
lines into the R command-line, and what I see is:
> chisq.test(matrix(c(3,6,3,4,4,
+ 4,1,4,6,5,
+ 2,7,4,2,5,
+ 8,2,4,4,2,
+
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
2005 Oct 25
1
Confidence Intervals for Mixed Effects
I'm fairly new to R and am wondering if anybody knows of R code to
calculate confidence intervals for parameters (fixed effects and variance
components) from mixed effects models based on Sattherthwaite's method?
I'm also interested in Satterthwaite-based confidence intervals for linear
combinations (mostly sums) of various variance components.
[[alternative HTML version
2012 Sep 01
1
Vectorial analogue of all.equal()?
Greetings All.
Once again, I am probably missing something fairly accessible,
but since I can't find it I'd welcome advice!
I have a dataframe derived from a text file of data in tabular
format. For one of the variables, say X, I want to select the
subsets which in which X equals a particular value.
Such values are given in the text file like: 2.3978953, and each
such value will occurr