similar to: odds ratio: how to create reference

Displaying 20 results from an estimated 5000 matches similar to: "odds ratio: how to create reference"

2008 Sep 29
2
density estimate
Hi, I have a vector or random variables and I'm estimating the density using "bkde" function in the KernSmooth package. The out put contains two vectors (x and y), and the R documentation calls y as the density estimates, but my y-values are not exact density etstimates (since these are numbers larger than 1)! what is y here? Is it possible to get the true estimated density at each
2008 Sep 22
2
Coefficients, OR and 95% CL
Dear R-users, After running a logistic regression, I need to calculate OR by exponentiating the coefficient, and then I need the 95% CL for the OR as well. For the following example (taken from P. Dalaagard's book), what would be the most straightforward method of getting what I need? Could anyone enlight me please? Thank you! Lucho > summary(glm(menarche~age,binomial)) Call:
2007 Nov 15
2
font formating
I am tryindo to do a very simple thing but cannont find how to do it anywhere. I need to formap part of my title as subscript ans superscript. How can I do it? Thanks a lot in advance José -- MSc José Alberto F. Monteiro Botanisches Institut Universität Basel [[alternative HTML version deleted]]
2009 Feb 19
2
read.table : how to condition on error while opening file?
Hi, I'm using read.table in a loop, to read in multiple files. The problem is that when a file is missing there is an error message and the loop is broken; what I'd like to do is to test for the error and simply do "next" instead of breaking the loop. Anybody knows how to do that? Example: filelist <- c("file1.txt", "file2.txt",
2009 Apr 07
4
group by-like statement for 2-row matrix
Hi, my problem is as follows: I have a matrix of two rows like this: 2 2 3 4 4 4 5 5 6 1 1 2 1 3 3 2 1 1 Can I apply something like "group by" in sql? What I want to achieve is the some of second row for each unique entry of first row: 2 -> 2 (=1+1) 3 -> 2 4 -> 7 (=1+3+3) 5 -> 3 (=2+1) 6 -> 1 Thanks!! Henning
2007 Oct 01
4
Disentagling formulas
I am writing a program in which I would like to take in a formula, change the response (Y) variable into something else, and then pass the formula, with the new Y variable to another function. That is, I am starting with formula <- Y~X1+X2+X3 and I'd like to do something like Y <- formula$Y newY <- f(Y) lm(newY~X1+X2+X3) So far, it seems that my
2007 Mar 01
7
count the # of appearances...
Hi there, is there a possibility to count the number of appearances of an element in a vector ? i mean of any given element.. deliver all elements which are exactly xtimes in this vector ? thx in advance !!
2008 Jul 12
5
shapiro wilk normality test
Hi everybody, somehow i dont get the shapiro wilk test for normality. i just can?t find what the H0 is . i tried : shapiro.test(rnorm(5000)) Shapiro-Wilk normality test data: rnorm(5000) W = 0.9997, p-value = 0.6205 If normality is the H0, the test says it?s probably not normal, doesn ?t it ? 5000 is the biggest n allowed by the test... are there any other test ? ( i know qqnorm
2010 Apr 28
7
operator problem within function
Dear all, i have a problem with processing dataframes within a function using the "$". Here´s my code: recode_items = function(dataframe,number,medium=2){ # this works q<-paste("columna",number,sep="") # this does not work, particularly because "dataframe" is not processed # dataframe should be: givenframe$columnagivennumber
2007 Feb 27
5
Multiple conditional without if
Dear all, i am stuck with a syntax problem. i have a matrix which has about 500 rows and 6 columns. now i want to kick some data out. i want create a new matrix which is basically the old one except for all entries which have a 4 in the 5 column AND a 1 in the 6th column. i tried the following but couldn´t get a new matrix, just some wierd errors:
2008 Jan 06
3
run setwd at the launch of R
Dear all, my R files (and the .csv files as well) are saved somewhere pretty deep down my hard disk. i have to chage to working directory therefore everytime i run R (i run it on powerPC mac), which is disgusting. using the setwd command at the beginning of an R script doesnt really help because i have to find this file first by hand. I am looking for possibility to run setwd during the
2009 Feb 17
3
Combination
Hello, I have a sequence of numbers: seq(1:50) and I would like to have all the possible combinations with this numbers without repeating any combination: 11, 12, 13, ... ,22,23,24,... How can I do it? Best, Dani -- Daniel Valverde Saub? Grup de Biologia Molecular de Llevats Facultat de Veterin?ria de la Universitat Aut?noma de Barcelona Edifici V, Campus UAB 08193 Cerdanyola del Vall?s-
2009 Mar 24
4
multiple paired t-tests
Hi R users, I have a very large data set that has two conditioning variables for the test I want to perform. A toy set can be simulated: type<-sample(1:3,100,replace=TRUE) class<-sample(1:20,100,replace=TRUE) value<-rnorm(100) data<-cbind(type,class,value) (though type and class are alphanum) I want to perform the three pair-wise t-tests between types for each class in data. Can
2007 Mar 07
5
hwo can i get a vector that...
dear all, how can i get a vector that shows the number of the column of matrix that contains the maximum of the row ?? can?t believe in need a loop for this... i have a 100 x 3 matrix and want to get a 100 x 1 vector with values 1,2,3 . there must be a simple solution. i just cannot find it. i think am searching on the wrong end. thx for help in advance. m.
2010 Jun 01
3
lapply with functions with changing parameters
Dear all, I am trying to avoid a for loop here and wonder if the following is possible: I have a data.frame with 6 columns and i want to get a cross-correlogram (by using ccf) . Obivously ccf only accepts two columns at once and then returms a list. In fact, with a for loop i?d do the following for (i in 1:6) { x[[i]]=ccf(mydf[,i],mydf[,6]) } Is there any chance to the same with
2009 Apr 07
6
Sequences
Hi, I am trying to make a sequence and am using a for loop for this. I want to start off with an initial value ie S[0]=0 then use the loop to create other values. This is what I have so far but I just keep getting error messages. #To calculate the culmulative sums: s<-rep(0,207) #as this is the length of the vector I know I will have s<-as.vector(s)
2008 Sep 17
3
t-test between percentages
Hi all, though i know this is a simple question, i really hope someone could. I am just trying to compare percents respectively the difference in percents by a simple test. t.test usually compares means and is working like it is supposed to be. Now i wonder how i can use a test in R to test for significant difference between two percentages.
2009 Apr 08
2
Null-Hypothesis
Hello R users, I've used the following help two compare two regression line slopes. Wanted to test if they differ significantly: Hi, I've made a research about how to compare two regression line slopes (of y versus x for 2 groups, "group" being a factor ) using R. I knew the method based on the following statement : t = (b1 - b2) / sb1,b2 where b1 and b2 are the two slope
2010 Feb 03
1
plm package index
Dear all, i just wonder if there´s a way to use a two column time index field in plm package. the manual says the following concerning data indexing: a character vector of length two containing the names of the individual and the time index, What would y´all do with a quarterly dataset that contains one column for the period and one for the year. Do I have to convert it to one single date
2009 Jan 13
5
indexing question
Hi all, i have a pretty easy indexing question, at least i believe so. The main reason i post it here, is that brackets and $ are hard to google. How do I index correctly, if i just want to display the whole dataset conditioned on the fact that some particular column equals one. I know i can do something like: data$somecolumn[data$particularcol ==1] . That will show all "some