Displaying 20 results from an estimated 10000 matches similar to: "How to test frequency independence (in a 2 by 2 table) with many missing values"
2009 Jul 19
1
Can I use "mcnemar.test" for 3*3 tables (or is there a bug in the command?)
Hello all,
I wish to perform a mcnemar test for a 3 by 3 matrix.
By running the slandered R command I am getting a result but I am not sure I
am getting the correct one.
Here is an example code:
(tt <- as.table(t(matrix(c(1,4,1 ,
0,5,5,
3,1,5), ncol = 3))))
mcnemar.test(tt, correct=T)
#And I get:
McNemar's Chi-squared
2009 Jun 01
1
using "cochran.test()" as a "mcnemar.test()" ?
Hello all
I wish to perform a mcnemar.test() for a 5X5 matrix.
Wikipedia tells me (http://en.wikipedia.org/wiki/Cochran_test) I should turn
to cochran.test.
The only place I found it was in the "outliers" package, but the command
cochran.test() acts differently then mcnemar.test() , and doesn't take a
table as input.
Any ideas on how to use it ?
#Example code:
aa =
2009 Dec 02
1
Generate missing data patterns
Dear R-users,
i try to generate missing values in a matrix X according to a given
missingnes pattern R with the probabilities p per row.
X<-matrix(rnorm(3*100),ncol=3)
## indicator matrix for missingnes (1 observed, 0 missing)
R<-matrix(c(1,1,1,
0,0,1,
1,1,0,
0,1,1),ncol=3,byrow=TRUE)
## probabilities for row 1, row 2, row 3 and row 4
2010 Mar 13
1
What can I use instead of ks.test for the binomial distribution ?
Hello all,
A friend just showed me how ks.test fails to work with pbinom for small
"size".
Example:
x<-rbinom(10000,10,0.5)
x2<-rbinom(10000,10,0.5)
ks.test(x,pbinom,10,0.5)
ks.test(x,pbinom,size = 10, prob= 0.5)
ks.test(x,x2)
The tests gives significant p values, while the x did come from
binom with size = 10 prob = 0.5.
What test should I use instead ?
Thanks,
Tal
2011 Sep 07
4
suggestion for proportions
Hi, I am wondering if anyone can suggest how to test the equality of 2 proportions. The caveat here is that the 2 proportions were calculated from the same number of samples using 2 different tests. So essentially we are comparing 2 accuracy rates from same, say 100, samples. I think this is like a paired test, but don't know if really we need to consider the "paired" nature of the
2010 Feb 25
1
How to do: Correlation with "blocks" (or - "repeated measures" ?!) ?
Hello dear R help group,
I have the following setup to analyse:
We have about 150 subjects, and for each subject we performed a pair of
tests (under different conditions) 18 times.
The 18 different conditions of the test are complementary, in such a way so
that if we where to average over the tests (for each subject), we would get
no correlation between the tests (between subjects).
What we wish
2010 Nov 29
1
cross tabulate variables by subject id
Dear list,
I have data like this:
dat1 <- data.frame(subject=rep(1:10,2),
cond1=rep(c("A","B"),each=5),
cond2=rep(c("C","D"),each=10),
choice=sample(0:1,10,replace=TRUE))
I would like to compare subjects' "choice" for (cond1=="A" &
cond2=="C") vs
2010 Jan 13
2
Simulation numbers from a probability table
Dear friends,
If I have a table like this, first row A B C D ... are different
levels of the variable, first column 0 1 2 4 ... are the levels of the
"numbers", the numbers inside the table are the probabilities of the
"number" occuring.
A B C D ...
0 0.2 0.3 0.1 0.05
1 0.1 0.1 0.2 0.2
2 0.02 0.2 0 0.1
4 0.3 0.01 0.01
2009 Nov 18
2
Importing tRNA data into R ?
Hello dear R help group,
I would like to download the tRNA data on:
http://gtrnadb.ucsc.edu/download.html
And then import it into R.
Can anyone direct me as to how to do so?
Thanks,
Tal
----------------------------------------------
My contact information:
Tal Galili
E-mail: Tal.Galili@gmail.com
Phone number: 972-52-7275845
FaceBook: Tal Galili
My Blogs:
http://www.talgalili.com (Web and
2010 Aug 18
1
Displaying Results in Two Columns
Could I have some suggestions as to how (various ways) I can display my confidence interval results?
rm(list = ls())
set.seed(1)
func <- function(d,t,beta,lambda,alpha,p.gamma,delta,B){
d <- c(5,1,5,14,3,19,1,1,4,22)
t <- c(94.32,15.72,62.88,125.76,5.24,31.44,1.048,1.048,2.096,10.48)
post <- matrix(0, nrow = 11, ncol = B)
theta <- c(lambda,beta)
beta.hat <- 2.471546
for(j
2009 Nov 20
6
How to: highlight R syntax on webpages ?
My question if in the Subject, but if to extend: I am specifically curious
about WordPress blogs. But any solution will give me a lead.
Thanks,
Tal
----------------------------------------------
Contact me: Tal.Galili@gmail.com | 972-52-7275845
Read me: www.talgalili.com (Hebrew) | www.biostatistics.co.il (Hebrew) |
www.r-statistics.com/ (English)
[[alternative HTML version deleted]]
2009 Oct 14
2
Scatter plot using icons (from a gif) instaed of points - is it possible ?
Hello dear R-help group.
I wish to plot a scatter plot using icons (or images) instead of points.
Is it possible? and how so?
Thanks,
Tal
----------------------------------------------
My contact information:
Tal Galili
E-mail: Tal.Galili@gmail.com
Phone number: 972-52-7275845
FaceBook: Tal Galili
My Blogs:
http://www.talgalili.com (Web and general, Hebrew)
http://www.biostatistics.co.il
2011 Jan 24
2
Implementing step-wise linear regression
Dear R fans,
I am trying to do step-wise linear regression using the F-test to decide
which variables to admit. Ewout Steyerberg suggests using the F-test for
this purpose.
I first build a model using no variables using lm(y ~ 1) and then using one
variable that is a strong predictor using lm(y ~ x). When I call var.test
on these two models, I do not get a significant p-value—0.07. But a
2009 Mar 01
1
SPSS repeated interaction contrast in R
dear all,
i'm trying to reproduce an spss-anova in R.
It is an 2x3x3 repeated measures desingn with repeated contrasts.
In R i've coded a contrast matrix for all factors and made a
split in the aov summary - but I can't get the repeated interaction contrasts.
The output from SPSS looks like this:
TaskSw * CongNow * CongBefore: SS df Mean Square F Sig.
1 vs. 2 1 vs. 2 1 vs. 2
2010 May 22
2
Capturing R console output into a file (sink+savehistory ??)
After reading more, I understand I didn't formulate my last question
correctly, so please allow me to rephrase:
What I am looking for is a way to save the R console session output.
That is, a command that would combine the results of using:
?sink # And
?savehistory
My motivation for this is that doing it will allow someone who is a blind
user of R to be able to easily export his results to
2009 Jul 25
2
labelling points plotted in a 2D plan
I created a 2 D plan:
> plot(range(-2.5,0.95),range(0.00,1.00),type="n",axes=TRUE)
I made a projection of points with their coordonates (X,Y) in that plan
> fullpoints=read.csv2("fullpoints.csv",h=T)
> plot(fullpoints)
The points are listed in that .csv file it is organized this way:
0,48875 0,142857143
0,409 0,142857143
0,45611 0,25
0,49833 0,222222222
0,61158
2010 Dec 14
1
rpart - how to estimate the “meaningful” predictors for an outcome (in classification trees)
Hi dear R-help memebers,
When building a CART model (specifically classification tree) using rpart,
it is sometimes obvious that there are variables (X's) that are meaningful
for predicting some of the outcome (y) variables - while other predictors
are relevant for other outcome variables (y's only).
*How can it be estimated, which explanatory variable is "used" for which of
2010 May 08
3
Count cases in a list
Hi everybody, I would like to count how many times names in list L,
nombreL, apear in list C, nombreC.
Can I improve the next program?
cuenta <- 0
topL <- length(nombreL)
topC <- length(nombreC)
for (i in 1:topL) {
for (j in 1:topC) {
k <-
grep(noquote(nombreL[i]),nombreC[j])
2010 Jul 02
3
Combining several plots besides a dendrogram?
Hello all,
I would like to recreate the plot shown here (from a useR 2009
presentation):
http://www.agrocampus-ouest.fr/math/useR-2009/abstracts/pdf/Hocking.pdf
I downloaded the code for that image, and discovered that it relies on
external web services, and also having PERL installed on the computer.
I believe this could be done "locally" using the "seqLogo"
2010 Nov 09
3
Is there a way to have 'comment' keep a list?
Hello all,
I recently discovered the "comment" command.
I see it can only hold a vector of characters.
Is there a way (or an alternative), to make it possible to have it keep a
list?
(for example, to keep different pieces of information like date of creation,
information of each variable and so on)
The closest solution I can think of is using 'names' on the vector, like
this: