Displaying 20 results from an estimated 2000 matches similar to: "chisq.test: decreasing p-value"
2009 Nov 22
3
Define return values of a function
I have created a function to do something:
i <- factor(sample(c("A", "B", "C", NA), 793, rep=T, prob=c(8, 7, 5,
1)))
k <- factor(sample(c("X", "Y", "Z", NA), 793, rep=T, prob=c(12, 7, 9,
1)))
mytable <- function(x){
xtb <- x
btx <- x
# do more with x, not relevant here
cat("The table has been created,
2009 Mar 08
1
Summary of data.frame according to colnames and grouping factor
A dataframe holds 3 vars, each checked true or false (1, 0). Another
var holds the grouping, r and s:
### start:example
set.seed(20)
d <- data.frame(sample(c(0, 1), 20, replace=T), sample(c(0, 1), 20,
replace=T), sample(c(0, 1), 20, replace=T))
names(d) <- c("A", "B", "C")
e <- rep(c("r", "s"), 10)
### end:example
How do I get the
2009 Mar 07
2
Recode factor into binary factor-level vars
How to I "recode" a factor into a binary data frame according to the
factor levels:
### example:start
set.seed(20)
l <- sample(rep.int(c("locA", "locB", "locC", "locD"), 100), 10,
replace=T)
# [1] "locD" "locD" "locD" "locD" "locB" "locA" "locA" "locA"
2010 Nov 17
2
slicing list with matrices
A list contains several matrices. Over all matrices (list elements) I'd like to access one matrix cell:
m <- matrix(1:9, nrow=3, dimnames=list(LETTERS[1:3], letters[1:3]))
l <- list(m1=m, m2=m*2, m3=m*3)
l[[3]] # works
l[[3]][1:2, ] # works
l[[1:3]][1, 1] # does not work
How can I slice all C-c combinations in the list?
S?ren
--
S?ren Vogel, Dipl.-Psych. (Univ.), PhD-Student, Eawag,
2009 Nov 13
1
shrink list by mathed entries
Hello
a <- c("Mama", "Papa", "Papa; Mama", "", "Sammy; Mama; Papa")
a <- strsplit(a, "; ")
mama <- rep(F, length(a))
mama[sapply(a, function(x) { sum(x=="Mama") }, simplify=T) > 0] <- T
papa <- rep(F, length(a))
papa[sapply(a, function(x) { sum(x=="Papa") }, simplify=T) > 0] <- T
# ... more
2010 Dec 03
1
Linear separation
In https://stat.ethz.ch/pipermail/r-help/2008-March/156868.html I found what linear separability means. But what can I do if I find such a situation in my data? Field (2005) suggest to reduce the number of predictors or increase the number of cases. But I am not sure whether I can, as an alternative, take the findings from my analysis and report them. And if so, how can I find the linear
2009 Mar 06
4
Summary grouped by factor
### example:start
v <- sample(rnorm(200), 100, replace=T)
k <- rep.int(c("locA", "locB", "locC", "locD"), 25)
tapply(v, k, summary)
### example:end
... (hopefully) produces 4 summaries of v according to k group
membership. How can I transform the output into a nice table with the
croups as columns and the interesting statistics as lines?
Thx,
2009 Nov 13
0
Craddock-Flood Test in R?
Hello
The "Craddock-Flood Test" is recommended for large tables with small
degrees of freedom and low-frequency cells. Is there an R procedure
and/or package which does the test?
Thank you for your help!
S?ren Vogel
--
S?ren Vogel, Dipl.-Psych. (Univ.), PhD-Student, Eawag, Dept. SIAM
http://www.eawag.ch, http://sozmod.eawag.ch
2010 Dec 27
0
Nagelkerke R square for Prediction data
Hello
I found some small postings dated to 22 Oct 2008 on the message subject. Recently, I have been working with binary logistic regressions. I didn't use the design package. Yet, I needed the "fit" indices. Therefore, I wrote a small function to output the Nagelkerke's R, and the Cox-&-Snell R from a fitted model. I am no professional programmer by far, yet, I hope, that
2010 Jul 23
0
ROpenOffice (which requires Rcompression)
Hello, for my data preparation and administration (data, labels, etc.) I use OpenOffice.org ODS spreadsheet files with several sheets in one file. However, I find it inconvenient to export every single sheet to a csv file whenever I apply changes to the labelling or so, and I haven't found a plugin or an application which does this batch in OOorg. Is there new development on a direct import
2000 Nov 16
2
newbee question
Dear All
Where can I lookup good methods to compute
p from q=bin(m,n)p^n*(1-p)^(m-n) such that
q<=alfa, alfa small. Are there such libs,
code and source in R?
Best Regards
--
Jan Burse SIAM, EAWAG
Scheuchzerstr. 67 ?berlandstr. 133
8006 Z?rich 8600 D?bendorf
tel: +41-1-364 17 66 tel: +41-1-823 55 34
2008 Sep 07
2
Regression with nominal data
Hi,
y is nominal (3 categories), x1 to 3 is scale. What I want is a
regression, showing the probability to fall in one of the three
categories of y according to the x. How can I perform such a
regression in R?
Thanks for your help
S?ren
2010 Jan 29
2
cbind, row names
Hello,
I read the help as well as the examples, but I can not figure out why
the following code does not produce the *given* row names, "x" and "y":
x <- 1:20
y <- 21:40
rbind(
x=cbind(N=length(x), M=mean(x), SD=sd(x)),
y=cbind(N=length(y), M=mean(y), SD=sd(y))
)
Could you please help?
Thank you
S?ren
2010 Apr 16
2
Return a variable name
Hello,
how can I return the name of a variable, say "a$b", from a function?
fun <- function(x){
return(substitute(x));
}
a <- data.frame(b=1:10);
fun(a$b)
... returns a$b, but this is a type language, thus I can't use it as a
character string, can I? How?
Thanks for help,
S?ren
2010 May 08
2
Adding NAs to data.frame
Hello, after the creation of a data.frame I like to add NAs as follows:
n <- 743;
x <- runif(n, 1, 7);
Y <- runif(n, 1, 7);
Ag6 <- runif(n, 1, 7);
df <- data.frame(x, Y, Ag6);
# a list with positions:
v <- apply(df, 2, function(x) sample(n, sample(1:ceiling(5*n/100), 1), repl=F));
# a loop too much?
for (i in 1:length(df)){
df[unlist(v[i]), i] <- NA;
}
summary(df);
This
2009 Feb 27
2
add absolute value to bars in barplot
Hello,
r-help at r-project.orgbarplot(twcons.area,
beside=T, col=c("green4", "blue", "red3", "gray"),
xlab="estate",
ylab="number of persons", ylim=c(0, 110),
legend.text=c("treated", "mix", "untreated", "NA"))
produces a barplot very fine. In addition, I'd like to get the
2006 Jun 14
1
Estimate region of highest probabilty density
Estimate region of highest probabilty density
Dear R-community
I have data consisting of x and y. To each pair (x,y) a z value (weight) is assigned. With kde2d I can estimate the densities on a regular grid and based on this make a contour plot (not considering the z-values). According to an earlier post in the list I adjusted the kde2d to kde2d.weighted (see code below) to estimate the
2008 Oct 09
2
Plot grouped histograms
r11 -- r16 are variables showing a reason for usage of a product in 6
different situations. Each variable is a factor with 4 levels imported
from a SPSS sav file with labels ranging from "not important" to "very
important", and NA's for a sample of N = 276.
(1) I need a chi square test of independence showing that the reason
does not differ depending on the
2008 Jun 25
1
help_transformation
heya,
i am fitting linear mixed effect model to a response Y. Y shows an s-shaped distribution when using QQ-plots (some zero values and some very high values). hence, which transformation should i apply that Y follows a normal distribution? any r-function/package available to do this?
thanks for any hint,
regards,
lukas
???
Lukas Indermaur, PhD student
eawag / Swiss Federal Institute of
2007 Feb 20
1
testing slopes
Hello
Instead of testing against 0 i would like to test regression slopes against -1. Any idea if there's an R script (package?) available.
Thanks for any hint.
Cheers
Lukas
???
Lukas Indermaur, PhD student
eawag / Swiss Federal Institute of Aquatic Science and Technology
ECO - Department of Aquatic Ecology
?berlandstrasse 133
CH-8600 D?bendorf
Switzerland
Phone: +41 (0) 71 220