[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

[Uwe Ligges]

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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