similar to: Multiple Paired T test from large Data Set with multiple pairs

Is there an optimal / minimum sample size for attempting to construct a classification tree using /rpart/? I have 27 seagrass disturbance sites (boat groundings) that have been monitored for a number of years. The monitoring protocol for each site is identical. From the monitoring data, I am able to determine the level of recovery that each site has experienced. Recovery is our

Dear R list, I am having some trouble drawing a bar-graph with two groups, both of which are stacked. A sample of my data (IUCN and national conservation status for marine and terrestrial species) look like this: Status IUCN Terrestrial IUCN Marine National CS Terrestrial National CS Marine NE 168 69 16 69 LC 41 6 148 6 NT 5 4 7 4 VU 4 2 7 2 EN 4 2 4 2 CR 1

Dear R list, It appears that my request from yesterday got a bit garbled. I have tried to rephrase and retype it - please let me know if you can help me - I am having some trouble drawing a bar-graph with two groups, both of which are stacked. I would like to plot the conservation status according to two classifications (i.e. my groups - IUCN status and national status), and for each of those

Hi: I am a very recent user of R 1.40 for MacOSX and went through the help files but did not not find the function that I am looking for. I have two comma separated files which I want to partly combine. File 1 has 49670 lines and 26 columns (separated by commas) and looks like this: ...

Hi, I'm trying to set up R to run a simulation of two populations in which every 3.5 days, the initial value of one of the populations is reset to 1.5. I'm simulation an experiment we did in which we fed Daphnia populations twice a week with algae, so I want the initial value of the algal population to reset to 1.5 twice a week to simulate that feeding. I've use for loops and if/else

Hi, I am currently trying to do a GLMM on a dataset with percent cover of seagrass (dep. var) and a suite of explanatory variables including algal (AC) and epiphyte cover (EC), rainfall, temperature and sunshine hours. M2=glmer(SG~AC+EC+TP+SS+RF+(1|Location/fSi/fTr), family=binomial,data=data,nAGQ=1) As the dependent variable is percent cover, I used a binomial error structure. I also have a

Hi all, I am applying a Presence/absence Generalized additive model to model the distribution of marine algae species in R. I have found that log transforming the environmental variables improves the explained deviance of the model considerably. While log transforming is common practice in GLM, I have been unable to find any papers where this is performed in a GAM. Im wondering whether this

Hello, we want to identify breakpoints (different phases) in environmental data, algae cell counts of three years with intervals between 7 and 30 days (N=40). We found that breakpoints(cells ~1) works great and identifies 5 very good breaks, however we are uncertain about these, because the data are unequally spaced. Is there a way to include the information about the measurement intervals,

Dear R, I have a question concerning quantile regression models. I am using the quantile regression model to test the relationship between abalone and the percentage cover of algae etc at different sites and depths. An example is fit<-rq(abalone~%coversessileinvertebrates+factor(Depth)+factor(Site),tau=0.7) In this model depth is fixed and site is random. My question is, is it possible

Hi, my name is Luis, and I have a problem with a dataset. Its name is algae and count the collection of data in a lake and respective proliferation of algae. The parameters that it has are: "mxPH", "mnO2", "Cl", "NO3" "NH4", "oPO4", "PO4", "Chla" and "a1" all numerics. a1 - algae1 If I try to do SVM with

Hi, I am looking at the effect of allelochemicals produced by two freshwater macrophyte species on two different algal species at different days. I am comparing the effect of each macrophyte on each algae at each day. I received help from someone doing the LMEM (Linear mixed-effect models) and he told me to do ANOVA to analyse the LMEM. However, I received these feedback from my examinor; 1. An

Hi all, I am fairly new to R and I am trying to run mvpart and create a MRT using explanatory variables and covariables. I've been following the procedures in Numerical Ecoogy with R. The command (no covariables) which works fine - ABUNDTMRT <- mvpart(abundance ~ .,factors,margin=0.08,cp=0,xv="1se",xval=nrow(abundance),xvmult=100,which=4) where abundance is 4th root

Hi, I'm trying to analyse a hierachical design and am running into some trouble. Clearly I don't fully understand "Error" and I was hoping someone could set me straight. We measure percentage algal cover in each of 5 quadrats from each of 16 patches where 4 treatments are randomly allocated to a patch. First suppose patches are coded 1 to 16. then the following gives the

Saludos, tengo una base de datos con tres variables: especie, tratamiento y abundancia. Quiero hacer comparaciones múltiples con Tukey. Ya había usado el comando TukeyHSD(aov(x~y)). La cuestión esque ahora tengo varios niveles del factor especie y varios niveles del factor tratamiento. Si hago TukeyHSD(aov(abundancia~especie:tratamiento)) me salen todas las comparaciones posibles, pero yo sólo

Hi, I'm trying to build a mixed-effects model in which I'd like to include either a distance matrix or a phylogenetic tree as a random effect. The troubles I've had are that: 1. Function lmer() in package lme4 only accepts a data frame column as a random factor and not a distance matrix. 2. Function MCMCglmm() in package MCMCglmm only accepts a rooted and ultrametric phylogenetic

Dear colleagues, I have a data from a repeated measures design that I'm analysing through a mixed model. Nine independent sampling units (flasks with culture medium with algae) were randomly divided into 3 groups ("c", "t1", "t2"). There is no need for inclusion of the random effect of the intercept, because the nine sample units are homogeneous among each other

Hi all, I've used R for basic programming and data management for a few years now. One of the things that I think could be improved is the data editor. Its a great feature and I use it alot by calling edit(data.frame); very useful to see if what you tried to do actually worked. However, one of the annoying things about it is that when you scroll down the window it doesnt show you all the

Hello all. I've been a fan of the xiph project for some time, thank you for your excellent work. I am looking for a fully-developed, beta, or alpha open-source hardware platform for remote deployment to terrestrial fm transmitters and streaming to general internet listeners. Willing to participate in development/beta testing of projects or possible $ support for an existing project. Able

I try memory.size function to find out available memory size, but surprisingly R complains it can't find the function. ?memory.size also failed. Is it not in the base library? If so, why can't my R find it? I am using the binary 1.9.0 version for Mandrake 9.1. Thanks in advance. Daehyok Shin Terrestrial Hydrological Ecosystem Modellers Geography Department University of North

Greetings, I have some confusion with the use of if - else. Let's say I have a four variables as follows: Condition DateFound DateFirstEvent DateSecondEvent NA 10Jan2000 NA NA 0 05Jan2000 07Jan2000 10Jan2000 1 07Jan2000 07Jan2000