search for: treatmens

Dear All user, Hello, I'm a student and I have some trouble with the experimental (columns-experiments) design of my project. I use a randomized block design with 4 treatments including a control. For each treatment, I use 3 replicates and 3 blocks. The treatments are: -T1 = COD (300 mg/Lit) COD=chemical oxygen demand -T2 = COD (200 mg/Lit) -T3 = COD (100 mg/Lit) -T4 = COD (0 mg/Lit) as

Hi, I was trying to figure out how to do post-hoc tests for Two Way ANOVAs and found the following 2 approaches: a. Do pairwise t-tests (bonferroni corrected) if one finds significance with the ANOVA. Link- http://rtutorialseries.blogspot.com/2011/01/r-tutorial-series-two-way-anova-with.html b. Do TukeyHSD on an aov model Link-

Dear R gurus, I have the following model: appcov.aov <- aov(yield ~ prevyield + trt + block) where prevyield is a continuous numeric covariate and trt and block are factors (yes, I did factor()!) Now, when I do a TukeyHSD, my diff's are all screwed up! For instance: treatment mean for treatmen "E" is 277.25 and for treatment "O" is 279.5, so I figure the diff O-E

...OV, as explained showed in "Random and Mixed Effects", chapter 10, V./R., on a data set i collected on turf root density under different turf species, substrates, fertilisation and sampling depht. ..and 12 replicates So, on a general formulation, i have a response factor, say, Roots, treatmens T1, T2, T3 and T4, and Rep replicates, organized on a four levels split plot design. I have an old gwbasic program, simple and time tested, that can calculate the analisys of variance of 3 levels split plot experiment, and when i compare his output whit the results obtained with R, i find that i...

...rform AOV, as explained in "Random and Mixed Effects", chapter 10, V./R., on a data set i collected on turf root density under different turf species, substrates, fertilisation and sampling depht. ..and 12 replicates So, on a general formulation, i have a response factor, say, Roots, treatmens T1, T2, T3 and T4, and Rep replicates, organized on a four levels split plot design. I have an old gwbasic program, simple and time tested, that can calculate the analisys of variance of 3 levels split plot experiment, and when i compare his output whit the results obtained with R, i find that i...

....size) *********************************************************** My response variable is number of aphids/colony on shaded cocoa trees, measured over 15 days (which I treat as a random factor) in four sites (random factor), two levels of shade (fixed) within each site, and three aphid predation treatmens (fixed) within each shade level. My total N = 2,256 observations (actually counts). The comand lines were the same as in the example in: Crawley, M. J. 2002. Statistical Computing: an intro to data analysis using S-Plus. Wiley. pages: 702-704. My questions are: 1-Did I use the appropriate analy...

Dear R users, I am trying to estimate to estimate the average treatmen effect on the treated (ATT) using first the MatchIt software to weight the data set and, after this, the Zelig software as shown in Ho et al. (2007). See here for an explanation of how to apply this technique in R: http://imai.princeton.edu/research/files/matchit.pdf I encounter a slight problem when I apply the weights that