
Dear Uwe.

Many thanks for your reply.  I attach the data set that i use for the analyses.  Hopefully this will help you identify the problem.  I'm really new in using r so please bear with me.

All the best,
Kyriakos

> Date: Mon, 30 Apr 2012 15:20:04 +0200
> From: ligges@statistik.tu-dortmund.de
> To: antoniouky@hotmail.com
> CC: r-help@r-project.org
> Subject: Re: [R] Error in if (nuhat < 2) stop("The degrees of freedom must be greater than or equal to 2") : missing value where TRUE/FALSE needed
> 
> 
> 
> On 29.04.2012 16:28, Kyriakos Antoniou wrote:
> >
> > Hi,
> >
> > i am trying to run an ANCOVA and a bootstrapped ANCOVA analysis on a specific data set.  I am using the ancova and ancboot functions as in the following code:
> >
> > setwd("C:/Users/User/Desktop/Rdatabilingualstudy2012")
> >
> > bilingualismdata<-read.spss("bilingualdataforconferences2012.sav", use.value.labels = TRUE, to.data.frame = TRUE)
> >
> > bilingualismdata$TypeBiling<-factor(bilingualismdata$TypeBiling, levels = c(0:1), labels = c("monolingual", "bilingual"))
> >
> > cypriot<-subset(bilingualismdata, TypeBiling=="monolingual")
> > cypriotenglish<-subset(bilingualismdata, TypeBiling=="bilingual")
> >
> > covGrp1<-cypriot$FAS
> > dvGrp1<-cypriot$Simon
> > covGrp2<-cypriotenglish$FAS
> > dvGrp2<-cypriotenglish$Simon
> >
> > source("http://www-rcf.usc.edu/~rwilcox/Rallfun-v16")
> >
> > ancova(covGrp1, dvGrp1, covGrp2, dvGrp2)
> > ancboot(covGrp1, dvGrp1, covGrp2, dvGrp2, nboot = 2000)
> >
> >
> > However, i always get the following errors (note that i get these errors when i am running the analysis on a specific data set.  The same code works fine with other data sets):
> >
> >> ancova(covGrp1, dvGrp1, covGrp2, dvGrp2)
> > [1] "NOTE: Confidence intervals are adjusted to control the probability"
> > [1] "of at least one Type I error."
> > [1] "But p-values are not"
> > Error in if (nuhat<  2) stop("The degrees of freedom must be greater than or equal to 2") :
> >    missing value where TRUE/FALSE needed
> 
> Aleady the way the Note is printed shows the code is poorly written, the 
> non-working error message supports that.
> Since we do not have the data, we cannot help, probably lm() is capable 
> of the ancova you have in mind.
> 
> Uwe Ligges
> 
> 
> 
> 
> > In addition: Warning messages:
> > 1: In min(sub[vecn>= 12]) :
> >    no non-missing arguments to min; returning Inf
> > 2: In max(sub[vecn>= 12]) :
> >    no non-missing arguments to max; returning -Inf
> > 3: In near(x1, x1[isub[i]], fr1) : NAs introduced by coercion
> > 4: In near(x2, x1[isub[i]], fr2) : NAs introduced by coercion
> > 5: NAs introduced by coercion
> >
> >> ancboot(covGrp1, dvGrp1, covGrp2, dvGrp2, nboot = 2000)
> > [1] "Note: confidence intervals are adjusted to control FWE"
> > [1] "But p-values are not adjusted to control FWE"
> > [1] "Taking bootstrap samples. Please wait."
> > Error in if (nuhat<  2) stop("The degrees of freedom must be greater than or equal to 2") :
> >    missing value where TRUE/FALSE needed
> > In addition: Warning messages:
> > 1: In min(sub[vecn>= 12]) :
> >    no non-missing arguments to min; returning Inf
> > 2: In max(sub[vecn>= 12]) :
> >    no non-missing arguments to max; returning -Inf
> > 3: In near(x1, x1[isub[i]], fr1) : NAs introduced by coercion
> > 4: In near(x2, x1[isub[i]], fr2) : NAs introduced by coercion
> > 5: In near(x1, x1[isub[i]], fr1) : NAs introduced by coercion
> > 6: In near(x2, x1[isub[i]], fr2) : NAs introduced by coercion
> >
> > Any help with how i van solve this would be appreciated as i am really stack and don't really know what to do.
> >
> > Best,
> > Kyriakos
> 
> [irrelevant part deleted]
> 
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