similar to: Non-normal data issues in PhD software engineering experiment

Displaying 20 results from an estimated 10000 matches similar to: "Non-normal data issues in PhD software engineering experiment"

2005 May 04
4
rank of a matrix
how do I check the rank of a matrix ? say A= 1 0 0 0 1 0 then rank(A)=2 what is this function? thanks I did try help.search("rank"), but all the returned help information seem irrelevant to what I want. I would like to know how people search for help information like this. rank(base) Sample Ranks SignRank(stats) Distribution of the
2003 Jan 30
1
Kruskal-Wallis, Friedman tests and Tukey HSD
Dear all Is there any way of doing a Tukey HSD post-hoc test after a Kruskal- Wallis or Friedman rank sum test (in the ctest package)? Thanks in advance, Albertus Dr. Albertus J. Smit Department of Botany University of Cape Town Private Bag Rondebosch 7700 South Africa Tel. +27 21 689 3032
2012 Jan 10
4
2 sample wilcox.test != kruskal.test
Hello, I think I am right in saying that a 2 sample wilcox.test is equal to a 2 sample kruskal.test and a 2 sample t.test is equal to a 2 sample anova. This is also stated in the ?kruskal.test man page: The Wilcoxon rank sum test (wilcox.test) as the special case for two samples; lm together with anova for performing one-way location analysis under normality assumptions; with Student's t
2009 Oct 14
3
post-hoc test with kruskal.test()
Dear R users, I would like to know if there is a way in R to execute a post-hoc test (factor levels comparison, like Tukey for ANOVA) of a non-parametric analysis of variance with kruskal.test() function. I am comparing three different groups. The preliminary analysis using the kruskal-wallis-test show significance, but I still don''t know the relationship and the significance level
2005 Jan 17
5
find source code
I am using R 2.0.2 on a WinXP I am trying to get the code of the Kruskal-Wallis test but > kruskal.test function (x, ...) UseMethod("kruskal.test") <environment: namespace:stats> > ls(3) [1] "acf" "acf2AR" "add.scope" .............. [181] "kruskal.test" "ks.test"
2010 Feb 24
1
extracting results from wilcox_test (package::coin)
Recently, I ran a series of Kruskal-Wallace tests [kruskal.test()] using by() to group by site Output is a list: >Herb.KW Herb.df$ID: 10-1 Kruskal-Wallis rank sum test data: Indicator_Rating by Year Kruskal-Wallis chi-squared = 15.24, df = 7, p-value = 0.03302 ----------------------------------------------------------------------------------------------------- Herb.df$ID: 18-1
2008 Nov 12
2
creating a file of p.values
Hi all, I am performing hundreds of kruskal wallis tests and trying to figure out how to create a file of the p.values I obtain. This is the code I use for the tests: A2<-kruskal.test(X2~treatment) A3<-kruskal.test(X3~treatment) A4<-kruskal.test(X4~treatment) A5<-kruskal.test(X5~treatment) A6<-kruskal.test(X6~treatment) A7<-kruskal.test(X7~treatment)
2008 Aug 21
1
Kruskal.test() on lists
Hi, I am trying to do a kruskal wallis test on two lists, fVisited and cSN: fVisited[[1]] [1] 0.17097623 0.30376141 0.17577266 0.14951855 0.03959753 0.08096217 0.05744888 0.02196257.... .... cSN[[1]] [1] 0.08557303 0.36477791 0.19601252 0.12981040 0.05351320 0.10385542 0.03539577 0.03106175.... So if I just want to do a test on just one of the entries this is simple enough:
2013 Apr 15
1
Kruskal-Wallis
Hi, I have got two groups of samples; and for every row, I wish to calculate Kruskal-Wallis' p-value. In the example below, and the stars (****) show where I am struggling to design and put things together. Any help would be appreciated. myFile <- data.frame(Sample_1a = 1:10, Sample_1b = 2:11, Sample_1c = 3:12, Sample_2a=4:13, Sample_2b=7:16, row.names=LETTERS[1:10]) groups <- rep
2001 Feb 27
4
Post hoc tests
This is only partly an R question, but this seems a good place to ask. Like many, if not most, statistics programs, R has no post hoc tests for Kruskal Wallis or Friedman, and as far as I can make out they are not available in any of the R packages. I would be grateful if someone could point me in the right direction if I am wrong. As I said this is not uncommon. Parametric Anova procedures
2013 Jul 09
1
Kruskal.test
Hi, ?kruskal.test() ?a<- c(2,4,5,2,7) ?b<- c(2,2,6) ?c<- c(3,7,9,3) ?kruskal.test(list(a,b,c)) # ?#? Kruskal-Wallis rank sum test # #data:? list(a, b, c) #Kruskal-Wallis chi-squared = 2.003, df = 2, p-value = 0.3673 A.K. Hi I need an expression in R to apply a kruskal.test to this data (for example). a ? a ? a ? a ? ?a ? ?b ? b ? ?b ? ?c ? ?c ? c ? ?c 2 ?4 ? ?5 ? 2 ? ?7 ? ?2 ? 2 ?
2014 Apr 30
2
Anova 2 vías NO PARAMÉTRICO
Hola, tenemos como equivalencia no paramétrica al Anova de 1 vía el test Kruskal Wallis, pero ¿existe un test no paramétrico equivalente al Anova de 2 vías? Gracias. Saludos. -- Sec. Apoyo Estadístico. Servicio de Apoyo a la Investigación (SAI) Vicerrectorado de Investigación e Internacionalización. Universidad de Murcia Edif. SACE. Campus de Espinardo. 30100 Murcia @. mariaelvira.ferre en
2008 Oct 22
1
Saving kruskal wallis p-values
Hi everyone, I am working on analyzing spectra which requires hundreds of kruskal wallis tests to be performed. Once significant results are found post tests are performed ect. My questions are: how do I perform all these kw tests and save just the pvalues in a table? Is there anyway to have R automatically perform post tests if a result of p<0.05 is found? Currently when I run the test
2010 Feb 18
2
Extracting values from a list
I have run a kruskal.test() using the by() function, which returns a list of results like the following (subset of results): Herb.df$ID: 4-2 Kruskal-Wallis chi-squared = 18.93, df = 7, p-value = 0.00841 -------------------------------------------------------------------- Herb.df$ID: 44-1 Kruskal-Wallis chi-squared = 4.43, df = 6, p-value = 0.6187 So then, how do extract a vector
2010 Aug 03
3
Kruskal Walllis test
Hi all My data table (g) contains a continues data column (plant.height) and other columns (columns 8 to 57), each with number of levels of different factors. ANOVA test was done and the p-values were extracted as follos: a <- function(x) anova(lm(plant.height ~ x))$"Pr(>F)"[1] r<- apply(g[,8:57],2,a) If I try to do a Kruskal-Wallis test : kw <- function(x)
2009 Sep 07
1
Equivalence of Mann-Whitney test and Kruskal-Wallis test with k=2
Hi all, The Kruskal-Wallis test is a generalization of the two-sample Mann-Whitney test to *k* samples. That being the case, the Kruskal-Wallis test with *k*=2 should give an identical p-value to the Mann-Whitney test, should it not? x1<-c(1:5) x2<-c(6,8,9,11) a<-wilcox.test(x1,x2,paired=FALSE) b<-kruskal.test(list(x1,x2),paired=FALSE) a$p.value [1] 0.01587302 b$p.value [1]
2012 Jun 11
1
Kruskal Wallis Post hoc
Hi, I have searched and found a response to a question similar to mine but when I tried the code, R says it's not an actual function so I thought I'd ask here. http://r.789695.n4.nabble.com/file/n4633035/Cookies.csv Cookies.csv I have attached the data I am using. I am trying to look at two things: how moisture content changes over time, and how it changes along the length of a log
2008 Oct 16
2
Saving results of Kruskal Walis test
Hello, I am running Kruskal-Walis test in R. When I try to save results using write.table it gives me the following error : Error in as.data.frame.default(x[[i]], optional = TRUE, stringsAsFactors = stringsAsFactors) : cannot coerce class "htest" into a data.frame The overall code is as follows : >data_file = read.table("~/DATA.dir/data_file.txt", header=T)
2008 Mar 24
2
Newbie help with Sweave
I think I've gotten my Emacs/Sweave/R system set up correctly, thanks to Vincent and Jim, but I haven't been successful getting my first document produced. I'm trying to use one of Friedrich Leisch's examples, http://www.ci.tuwien.ac.at/~leisch/Sweave/example-1.Snw. I cut and pasted the text into a document sweaveexample.Rnw in Emacs. It seemed to be processed successfully with R:
2010 Oct 27
1
(no subject)
I am interested in using "multcompLetters" after running "kruskalmc" but I'm a newbie and I'm not having luck figuring it out. I can run "kruskalmc" just fine, but after studying the documentation for "multcompletters" for a long time, I cannot figure out how to make it work. Any ideas? R input is below > >> #here is my data set >>