similar to: difftime arguments

R-listers, I have noticed several posts on issues with difftime producing NA's but they have been for older versions of R. Here's the issue associated with difftime that I am dealing with in R 2.12.2. > preciptime = strptime("01/10/2007 14:00",format="%m/%d/%Y %H:%M") > class(preciptime) [1] "POSIXlt" "POSIXt" > # Now using difftime, this

Hi. I'm trying to take the difference in days between two times. Can you point out what's wrong, or suggest a different function? When I try the following code, The following code works fine: a <- strptime(1911100807,format="%Y%m%d%H",tz="GMT") b <- strptime(1911102718,format="%Y%m%d%H",tz="GMT") x <- difftime(b, a,

Hello everbody, i'm currently using the anova()-test for a small data.frame of 40 rows and 2 columns. It works well, but is there any preconditions for a valid variance analysis, that i should consider? Thank you for your answer, Daniel

Hello! you, Emil Bode <emil.bode at dans.knaw.nl>, wrote on Tuesday, July 31, 2018 1:55 PM: > Some of the changes you're proposing could be made (with effort), but note that you're not > restricted to providing strings with a format. > What you're trying to do can be accomplished with as.difftime(12, units='weeks'), see also > ?as.difftime > > Or if

Dear all, During my pre-R era I tried (yes, tried) to understand mixed models by working through the 'rat example' in Sokal and Rohlfs Biometry (2000) 3ed p 288-292. The same example was later used by Crawley (2002) in his Statistical Computing p 363-373 and I have seen the same data being used elsewhere in the litterature. Because this example is so thoroughly described, I thought

Dear R-core There is a different output for the apply function due to the change of unlist as mentioned in the R news. Newly, applying as.factor() (or factor()) in str(dat <- data.frame(x = 1:10, f1 = gl(2,5,labels = c("A", "B")))) (d1 <- apply(dat,2,as.factor)) newly returns a character matrix while in R-2.3.1 the same command resulted in an integer matrix that was

Dear all, I have a vector generated using the function strptime: > my.dt [1] "2004-04-19 08:35:00 W. Europe Daylight Time" "2004-04-19 09:35:00 W. Europe Daylight Time" "2004-04-19 11:35:00 W. Europe Daylight Time" [4] "2004-04-19 13:35:00 W. Europe Daylight Time" "2004-04-20 07:50:00 W. Europe Daylight Time" > class(my.dt) [1]

I am having trouble with creating a POSIXct object. If I create a variable of class Date first out of the date part of my data, I am ok, but if I just paste the date and time parts together and try and create the POSIXct object, I have problems. Here is a toy example created from the actual data which caused the problem. I am using R 2.0.1 on Windows XP. > # Data frame with dates and

Dear R-list I have a question concerning the argument "adjustSigma" in the function "lme" of the package "nlme". The help page says: "the residual standard error is multiplied by sqrt(nobs/(nobs - npar)), converting it to a REML-like estimate." Having a look into the code I found: stdFixed <- sqrt(diag(as.matrix(object$varFix))) if (object$method

hi list, i have to ask you again, having tried and searched for several days... i want to do a TukeyHSD after an Anova, and want to get the adjusted p-values after the Tukey Correction. i found the p.adjust function, but it can only correct for "holm", "hochberg", bonferroni", but not "Tukey". Is it not possbile to get adjusted p-values after

Buenas tardes a todos los participantes del foro. Me dirijo a vosotros porque estoy atascado con una duda de programación respecto al data frame: > dd # Data frame de 5 variables, leído de un archivo txt id sexo nacim origen final 1 1 0 02/09/1955 01/04/1985 01/02/2014 2 2 1 29/10/1951 15/08/1996 01/05/2009 3 3 0 30/10/1942 02/08/2000 01/02/2014 4 4 1

hi all, I wish to draw on the same graphic device 3 functions. But i don't want them to be on different graph, i want to compare them on the same I don't need mfrow or mfcol, I need something else... 1 graph on 1 device inside this graph 3 ploted function. I saw something unsing data.frame, but i think it's overkill, and something less complicated must exist, if not why? why not

Hi In mixed-model with lme() How can I obtain Type II SS or Type III SS for fixed effect? Thanks Julien

Hi, I'm studying math, and i have to make an analysys using Randomised Block Design. I have two factors, i know how to do this in Statistica, but how to do this in R, i read some manuals but the only thing that i have found was 2 factor ANOVA. Please could someone help me, or give some usefull links ?? Krzytsztof Suwada

Hi All. I need a bit of help extracting the residual error variance from the VarCorr structure from lmer. #Here's a 2-way random effects model lmer.1 <- lmer(rating ~ (1|person)+(1|rater), data = dat) #Get the structure vc.fit <- VarCorr(lmer.1) #results in..... $person 1 x 1 Matrix of class "dpoMatrix" (Intercept) (Intercept) 0.7755392 $rater 1 x 1 Matrix

useRs, A no doubt simple question, but I am baffled. Indeed, I think I once knew the answer, but can't recover it. The default contrasts for aov (and lm, and...) are contr.treatment and contr.poly for unordered and ordered factors, respectively. But, how does one invoke the latter? That is, in a data.frame, how does one indicate that a factor is an *ordered* factor such that

Hi all, I just want to understand how R computes p-value in a simple linear regression model? The reason is that in Matlab in the function which "evaluate standard errors for multivariate normal regression", it just provide estimates and standard errors, without giving out p-value, It computes t-statistics as follows: abs(beta_hat/std_beta_hat) how to go further to get p-value?

Hi, I have a model with differents observations Xi. Each observation belongs to a group, either A or B. I would like to minimize a fonction like : sum( Xi - Z)^2 + sum (Xi - aZ -b)^2 A B The first sum contains all observations from group A and the second all observations from group B. I want to find the Z-value wich minimize this function. a and b are predefined parameters.

Hi, I use anova() to find interaction effect and then I need to find data with main effect from those data with interaction effect. How to do that? I used : anova(lm(data~factor1*factor2)), then select data with interaction effect. Then I need to select those data also with main effect of factor1 or factor2, from previous selected data. How to do that? Many thanks for your time on my

Hey, I'm generating a .jpeg file for a web application passing parameters to R via cgi. R gets the parameters by using commandArgs, which are passed to a variable named j and z j<-commandArgs()[3] z<-commandArgs()[4] Later I want to use the characters strings of the argument which the variables are holding for my filename, e.g.: jpeg(file="d:/data/images/jz.jpeg",...)