similar to: Effect Size Formaula and Calulations in R

Hello, I am trying to do a logistic regression and have one predictor variable (x) that is ratio and two predictor variables (y and z) that are categorical. These have three levels each which I have called "High", "Medium" and "Low". My question: do I need to use a numerical coding scheme for the categorical variables as required by some statistical software

Hi all, I'm having trouble getting access to the pwr. This is on Ubuntu Lucid Lynx, 64 bit. I'm installing pwr via packages.install('pwr'), and loading it via library(pwr), both of which appear successful. Strangely, I never get access to the pwr object in R. I tried installing it to /usr/local/lib/R/site-library and ~/R/x86_64-pc-linux-gnu-library. I also tried installing it

Is anyone aware of a fast way of doing fisher's exact test for a series of 2 x 2 tables in R? The fisher.test is really slow if n1=1000 and n2 = 1000. -- Thanks, Jim. [[alternative HTML version deleted]]

Dear R Gurus, I have a problem related to plot. For example, I have two variables, pre and post. pre <- c(1,2,3,4,5) post <- c(2,5,7,2,3) How can I plot a line graph similar to this one? http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1847566&rendertype=figure&id=F1 Would you please provide me a keyword so that I can search. I don't know what is the name of this

Hi, I noted a discrepancy between R and openepi when I ran a fisher test with the same matrix. In R: > a=matrix(c(1,2,6,17), nrow=2) > a [,1] [,2] [1,] 1 6 [2,] 2 17 > fisher.test(a, conf.int=T) Fisher's Exact Test for Count Data data: a p-value = 1 alternative hypothesis: true odds ratio is not equal to 1 95 percent confidence interval: 0.02061498

Dear R helpers, I have a question regarding wordpress and R. I have asked this question in Wordpress support ( http://wordpress.org/support/topic/368312 ) but there is no answer so far, maybe the R community can have a better answer. I followed the excellent tutorial on r-statistics-blog ( http://www.r-statistics.com/2010/02/r-syntax-highlight-on-your-blog-a-wordpress-plugin/ ) to enable syntax

Dear R experts, I have plot the PDF of t distribution with df = 74. curve(dt(x,df=74),from=-4, to=4) how can I shade the area under curve (for example, col="red") from t=+- 1.996? Thank you. Regards, CH -- CH Chan Research Assistant - KWH http://www.macgrass.com

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

Dear all, I am trying to run a loop in my codes, but the software returns an error: "subscript out of bounds" I dont understand exactly why this is happenning. My codes are the following: rm(list=ls()) #remove almost everything in the memory set.seed(180185) nsim <- 10 mresultx <- matrix(-99, nrow=1000, ncol=nsim) mresultb <- matrix(-99, nrow=1000, ncol=nsim) N

Hi All, I'm fitting a Poisson regression. And I want to plot 95% Confidence Interval of Regression Estimates. After coming back to original scale (using following formula): exponential(estimate +/- 1.96*SE), at best I can get the output in the form of estimates, lower_limit, upper_limit values. As far I know forest() in metafor package needs input in the form of estimates and their

Hi, i have a question in R, How and what command you need to do to run a kruskal-wallis test without the built in command 'kruskal.test'? many thanks. _________________________________________________________________ [[alternative HTML version deleted]]

Hi everyone, I am trying to install R-2.6 over my 2.5.1 installation on Mac OS X 10.5. R version 2.5.1 (2007-06-27) I double-click the installer package, 1) Click Continue 2) Click Continue 3) Click Continue + Click Agree On the "Installation Type" dialog screen, all four options are grayed out, with skip beside them. The Install button is also grayed out. If I click the

Hi there, I've used R before, but I just got a new computer with Leopard and I'm having trouble installing. I download the installer, but when I reach the end of the install process, the "install" button remains gray and unclickable. I've tried both standard and custom, as well as installing on my flash disk, to no avail. Any suggestions? I'd rather not build from

Dear Sir Sir when I use "png" function to save graph. At last it is written dev.off(). it does not produce any postscript file. Please help in this regard Thank you -- AMINA SHAHZADI Department of Statistics GC University Lahore, Pakistan. [[alternative HTML version deleted]]

I've spent several hours trying to track the answer down myself and failed miserably so a simple question for everyone that will no doubt have a painfully obvious answer. What's the command to calculate the critical value of r using a two tailed test with a given alpha and degrees of freedom? I.e., alpha=0.05, df=18, two-tailed test, with the result being 0.4438 -- View this message in

Dear Sir I am Amit Nirmalkar, M. Sc. Statistics. I generally use SPSS package for analysis. I wanted to run Conditional Logistic Regression in SPSS but this technique is not available. So I thought of R s/w. I am totally blank about R. Can you please send me few of R. Also how to run Conditional Logistic Regression in R. Thanks -- Amit Nirmalkar [[alternative HTML version deleted]]

Dear R People: Is there a Quality Control in R book that would be accessible for undergraduates, please? I'm teaching a QC course in the fall semester and would be happy to have a Use R book or something like that, please. Thanks in advance, Erin -- Erin Hodgess Associate Professor Department of Computer and Mathematical Sciences University of Houston - Downtown mailto: erinm.hodgess at

Dear R Help, I read through the archives pretty extensively before sending this email, as it seemed there were several threads on using predict with GLM. However, while my issue is similar to previous posts (cannot get it to predict using new data), none of the suggested fixes are working. The important bits of my code: set.seed(644) n0=200 #number of observations

Hello: I sent this question the other day with the wrong subject heading and couple typos, with no response. So, here I go again, having made those corrections. I would like to estimate, for lack of a better description, a partially additive non-parametric model with the following structure: z~ f(x,y):w1 + g(x,y):w2 + e In other words, I'd like to estimate the marginals with respect to

I keep getting the 'memory.size' error message when I run a program I have been writing. It always it cannot allocate a vector of a certain size. I believe the error comes in the code fragement below where I have multiple arrays that could be taking up space. Does anyone know a good way around this? w1 <- outer(xk$xk1, data[,x1], function(y,z) abs(z-y)) w2 <- outer(xk$xk2,