similar to: t.test

Displaying 20 results from an estimated 20000 matches similar to: "t.test"

2008 Mar 15
1
Anova
Hi all, I apologize for what might be a silly question. I am interested in doing a one way anova. This is not too hard in and of itself, either with anova, aov or oneway.test . However, I need to 1) get pvalues, 2) do a posthoc analysis with Tukey HSD, 3) and have (sometimes) an unbalanced design. I just can't seem to put all the pieces together. Any suggestions? Thanks in advance, Dan.
2011 Nov 18
1
cca with repeated measures
Dear all, How can I run a constrained correspondence analysis with the following data: 15 animals were measured repeatedly month-wise (over to 2 years) according to ther diet composition (8 food categories). our data.frame looks like this: food 1 2 ... 8 sex season year animal freq 12 8 ... 1 0 summer 2011 1 freq 0 7 ... 0 1 winter 2011 1 ... freq 0 7 ... 0 1 spring 2011 15 We
2009 May 13
1
Anova
melt.updn <- structure(list(date = structure(c(11808, 11869, 11961, 11992, 12084, 12173, 12265, 12418, 12600, 12631, 12753, 12996, 13057, 13149, 11808, 11869, 11961, 11992, 12084, 12173, 12265, 12418, 12600, 12631, 12753, 12996, 13057, 13149), class = "Date"), variable = structure(c(1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L,
2010 Aug 18
3
How to read ANOVA output
Hi folks, Where can I find document re "how to read anova output"? Google found many of them. But seemingly non of them can explain to me following output:- > tabA = c(5.67, 5.67, 5.55, 5.57) > tabB = c(5.75, 5.47, 5.43, 5.45) > tabC = c(4.74, 4.45, 4.65, 4.94) > tabs = data.frame(tabA, tabB, tabC) > tablets = stack(tabs) > anova(lm(values ~ ind, data =
2010 Jan 19
5
OT: Software for specific visualisation of data...ideas?
Dear List, A student in the Department where I work would like to produce a graphic similar to this one: http://image.guardian.co.uk/sys-files/Guardian/documents/2009/09/16/Public_spending_160909.pdf Does anyone know if the figure in the pdf can be generated in a specific software application for example? Any suggestions would be most gratefully received by the student concerned. Many thanks,
2010 Jul 14
3
levene.test
I am trying to use Levene's test (of package car), but I do not understand quite well how to use it. '?levene.test' does not unfortunately provide any example. My data are in a data frame and correspond to 1 factor plus response. Could someone please give me an example about how to use the command levene.test(y, group) Thanks in advance, marta -- View this message in
2009 Sep 09
2
"predict"-fuction for metaMDS (vegan)
Dear r-Community, Step1: I would like to calculate a NMDS (package vegan, function metaMDS) with species data. Step2: Then I want to plot environmental variables over it, using function envfit. The Problem: One of these environmental variables is cos(EXPOSURE). But for flat releves there is no exposure. The value is missing and I can't call it 0 as 0 stands for east and west. Therefore I
2012 Dec 29
2
Error in plot.envfit(ef, p.max = 0.1) : (subscript) logical subscript too long
Hello there, I'm trying to plot vectors with p<0.1 in a NMDS ordination plot using p.max. Below the scripts I'm using. I guess I'm missing something! could you please give me a hand? species<-metaMDS(species_matrix)ef<-envfit(species,environmentaldata_file,permu=999,na.rm=TRUE)efplot(species, dis="sites")plot(ef,p.max=0.1) Error in plot.envfit(ef, p.max = 0.1) :
2006 Oct 31
3
one problem about how to hold graphic with R
Sorry to disturb you, but can you help me to solve one little problem? I want to draw a graphic after another with R but I cannot find the first one after that. Do you know the command to hold the graphic with R? I remember with Matlab you may use "hold on". Thanks. -- Baohua Yang Email:yangbaohua@gmail.com [[alternative HTML version deleted]]
2004 Nov 04
3
sub- and superscript in plot labels
Dear List, I need to add a subscript and a superscript to some of the ions in the labels on some plots. I have got to here but now I'm stuck: plot(1:10, xlab = expression(paste("nm SO"[4], " ", mu, "eq cm"^{-2}, " yr"^{-1}))) Which gives almost what I require. No matter what I tried, however, I could not get bot a sub script *and* a superscript
2009 Aug 08
2
Factor Analysis in R
Hi I am trying to run Factor Analysis using R...I am using the syntax factanal(m1, factors=3) but it's giving me an message Error in cov.wt(z) : 'x' must contain finite values only ...I am using a data set which is having only numeric variables and have some NA's also in it..What should I do next..Someone please help me out with the syntax..Thanks in advance Cheers Arup --
2009 Sep 15
5
identical(length(x), 1) returns FALSE, but print(length(x)) is 1, length(x)==1 is TRUE, and is.integer(lenght(x)) is TRUE????
Dear R, the condition: identical(length(x),1) returns FALSE but print(length(x)) returns 1 and: is.vector(x) is TRUE. is.integer(length(x)) is TRUE length(x) ==1 is TRUE I am puzzled. Regards -- Corrado Topi Global Climate Change & Biodiversity Indicators Area 18,Department of Biology University of York, York, YO10 5YW, UK Phone: + 44 (0) 1904 328645, E-mail: ct529 at york.ac.uk
2008 Feb 14
2
Does the t.test in R uses Welch procedure or ordinary student t-test?
En innebygd og tegnsett-uspesifisert tekst ble skilt ut... Navn: ikke tilgjengelig Nettadresse: https://stat.ethz.ch/pipermail/r-help/attachments/20080214/a0ea0e66/attachment.pl
2008 Mar 03
7
help for the first poster- a simple question
Hi, there, I cannot get accurate value for calculation. for example: ld<-sqrt(1*0.05*0.95*0.05*0.95) 0.05*0.95-ld=-6.938894e-18 0.05*0.95-ld==0 is False. I met this problem in my program, how can I handle it. Thanks. xj.
2010 Aug 21
4
basic hist() question
Hi list I loaded the content of a file dureetasks.txt to variable a. This file contains an interger per line. when I print a vector, it displays correctly. however, when I try to print the histogram, I get this error message > a=read.table("dureetasks.txt") > hist(a) Error in hist.default(a) : 'x' must be numeric Can you help please? regards -- PhD candidate in
2008 Nov 12
1
gam help (really a vegan question)
What does Generalized Cross Validation score mean. I preform and ordisurf on an ordination (nmds) with an environmental variable. I am trying to figure out "how well" the environmental varibles predict/explain the sites placements in species space. Any help would be greatly appreciated. Any pointers to literature... would be welcome. thanks in advance, -- Stephen Sefick Research
2005 Aug 16
2
problem using model.frame()
Hi I'm having a problem with model.frame, encapsulated in this example: y1 <- matrix(c(3,1,0,1,0,1,1,0,0,0,1,0,0,0,1,1,0,1,1,1), nrow = 5, byrow = TRUE) y1 <- as.data.frame(y1) rownames(y1) <- paste("site", 1:5, sep = "") colnames(y1) <- paste("spp", 1:4, sep = "") y1 model.frame(~ y1) Error in model.frame(formula, rownames,
2005 Nov 03
4
merging dataframes
Dear List, I often have to merge two or more data frames containing unique row names but with some columns (names) common to the two data frames and some columns not common. This toy example will explain the kind of setup I am talking about: mat1 <- as.data.frame(matrix(rnorm(20), nrow = 5)) mat2 <- as.data.frame(matrix(rnorm(20), nrow = 4)) rownames(mat1) <- paste("site",
2005 Aug 16
4
as.character and a formula
Dear list, given this formula: > fmla <- formula(y1 ~ spp1 + spp2 + spp3 + spp5) > fmla[[3]] spp1 + spp2 + spp3 + spp5 is this the intended behaviour of as.character: > as.character(fmla[[3]]) [1] "+" "spp1 + spp2 + spp3" "spp5" ? Where does the extra "+" come from? > as.character(fmla) [1] "~"
2008 Jul 23
2
Weighted variance function?
There is a R function to calculate weighted mean : weighted.mean() under stats package. Is there any direct R function for calculating weighted variance as well? [[alternative HTML version deleted]]