similar to: simple ANOVA problem

Dear list members, I have a statistical question, that doesn't belong to this list, and I apologise for that in advance but I would appreciate your help very much. Is there some convention for selecting the a level for significance testing in scientific (e.g. chemical processes) studies? Most people use the 0.05 level but I could not find a reference to justify this. Why not 0.01 or 0.1?

When I try to run the "sammon" function of the multiv package, I always get this error message: Error in as.vector(dist(a)) : couldn't find function "dist" It happens even with example(sammon). I am running R 1.5.0 on Win98 and I have still installed R 1.4.1 but it doesn't work on the old R version with the older multiv package either. Is there a problem with the

Please, forgive my ignorance on statistics, but I have a rather simple question concerning AIC. Small values of AIC mean good fit of the model. How about negative values of AIC? Is a model with AIC=0.5 considered to have better fit than a model with AIC=-500? I couldn't find anything explaining this in the documentation or any elementary statistics textbook that I have at my disposal. Thanks

Hello R Users, I am new to R. I have two data sets i) TOMS aerosol optical depth(AOD) and ii) TOMS ozone(O3). > > AOD data is on 1x1 grid and O3 data is on 5x5 grid. > > First I want to read AOD and O3 as it is and then I want to regrid AOD on > 5x5 grid as O3. > > Reading is first problem. > > FIRST PROBLEM READING AOD: > > AOD data is in following format: >

Dear R Users,i am very new to R. I want your help on an issue regarding distance matrix and cluster analysis i had discharge data of 4 rivers(a,b,c,d) in 4 vectors each having 364 values > dput(qmu)structure(list(a = c(0.26, 0.25, 0.25, 0.25, 0.24, 0.23, 0.22, 0.21, 0.21, 0.21, 0.2, 0.19, 0.19, 0.19, 0.19, 0.18, 0.18, 0.18, 0.17, 0.17, 0.17, 0.17, 0.17, 0.17, 0.17, 0.17, 0.17, 0.17, 0.17, 0.17,

Dear list, I am starting a new project in cmdscale, and I have a question regarding distance matrix and covariance matrix. Can anyone help me in this? I sent this message so many times but always bounced with no further explanation. (1) Can I use covariance as my distance matrix? (2) Any good reference in this matter? (3) is the approach that I wrote below valid? Thank you, ilham Below is what

Hello list members, I am new to this list and don't know very much about what R can do or how to program it, but I am interested in plotting 4 variables as sequential contour plots (or surface plots), something like the conditioning plots for 4 variables (coplot(X1~X2|X3+X4)). To be more specific, I need a tool that will automatically create contour (orsurface) plots of X1 vs X2 vs X3 for

Hello R Users, I have two data sets i) TOMS aerosol optical depth(AOD) and ii) TOMS ozone(O3). AOD data is on 1x1 grid and O3 data is on 5x5 grid. First I want to read AOD and O3 as it is and then I want to regrid AOD on 5x5 grid as O3. Reading is first problem. FIRST PROBLEM READING AOD: AOD data is in following format: ######### Latitute: 89.5 167 0 0 0 0 0 182 0 0 0 0 0 0 0 0 0 0 0 0 200

Dear R-users; Previously I posted a question about the problem of rank deficiency in summary.manova. As somebody suggested, I'm attaching a small part of the data set. #*************************************************** "test" <- structure(.Data = list(structure(.Data = c(rep(1,3),rep(2,18),rep(3,10)), levels = c("1", "2", "3"), class =

Hi First post and a relative R newbie.... I am using the vioplot library to produce some violin plots. I have an input CSV with columns off irregular length that contain NAs. I want to strip the NAs out and produce a multiple violin plot automatically labelled using the headers. At the moment I do this Code:? ds1 = read.csv("http://www.lecturematerials.co.uk/data/spelling.csv")

Hi I am carrying out some logit regressions and want to (a) make sure I'm taking the right approach and (b) work out how to carry out some additional analysis. So, to carry out a logit regression where the dependent variable is a factor db, I use something like: res1_l <- glm(formula = db ~ y1 + + y5, family = binomial(link = "logit")) summary(res1_l) ...which is, I hope

Dear list members, this is not an R question and forgive me for using the list for irrelevant questions, but this is the only place I know where I can find some good statisticians and I need an expert opinion. There is this power law kinetic model of the form: M=kt^n where t is the time, M is the fraction of drug released, k is the rate constant and n is an exponent related to the mechanism of

Hi folks, I am running a very simple regression using mylm <- lm(mass ~ tarsus, na.action=na.exclude) I would like the use the residuals from this analysis for more regression but I'm running into a snag when I try cbind(mylm$residuals, mydata) # where my data is the original data set The error tells me that it cannot use cbind because the length of mylm$residuals is

Dear R-users I have 5 dependent variables (y1 to y5) and one independent variable (x) and 3 conditioning variables (m, n, and 0). Each of the conditioning variables has 2 levels. I created 2*4 panel plots. xyplot(y1+y2+y3+y4+y5 ~ x | m*n*o,layout = c(4,2)) I would like to reorder the 8 panels. I tried to use index.cond (e.g., index.cond = list(c(1,3,2,4,5,7,6,8)) but it didn't work out.

I am unfamiliar with R and I’m trying to do few statistical things like GLM and GAM with it. I hope my following questions will be clear enough: My datas ( y(i,j ))are run off triangles for example : J=1 J=2 J=3 I=1 1 2 3 I=2 4 5 I=3 6 My model is : E[y(i,j)] =m(i,j) Var[y(i,j)] =constant *m(i,j) Log(m(i,j)) = eta (i,j) eta (i,j) = c + alpha(i)

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hello all - As I progress in R I am trying to automate functions I would have normally farmed out to Excel, SPSS or Statistica. Single factor anova is one of them. For example, a dataset from NIST StRD (http://www.itl.nist.gov/div898/strd/anova/AtmWtAg.html) has two groups: 1 2 107.8681568 107.8681079 107.8681465 107.8681344

I am using R 2.8 and the latest versions of RMySQL on a Windows XP 64 bit machine. I was wondering if someone could help me figure out how to use dbWriteTable without inserting \r into my table. Consider the following code snippet, which is run after I connect to my database. myDFOut = dbReadTable(conn, "myDF") print(myDFOut) myDFIn = data.frame(x=paste("x", 1:5, sep =

Dear members, I want to create 8 graphs and write it into one page using mfrow=c(4,2). How to make all graphs (including the titles, legends, line types) to be scale down (resized proportionally). As an illustration, below is the code: pdf("testmfrow.pdf") par(mfrow=c(4,2)) x<-seq(1:10) y1<-rnorm(10) y2<-rnorm(10,mean=2,sd=1) y3<-rnorm(10,mean=3,sd=1)

Complete newbie to R -- struggling with something which should be pretty basic. Trying to create a simple data set (which I gather R refers to as a data.frame). So > a <- c(1,2,3,4,5); > b <- c(0.3,0.4,0.5,0,6,0.7); Stick the two together into a data frame (call test) using cbind > test <- data.frame(cbind(a,b)) Seems to do the trick: > test a b 1 1 0.3 2 2 0.4 3 3

Hi, I am very new to R and I've been trying to work through the R book to gain a better idea of the code (which is also completely new to me). Initially I imputed my data from a text file and that seemed to work ok, but I'm trying to examine linear relationships between gdist and gair, gdist and gsub, m6dist and m6air, etc. This didn't work and I think it might have something to do