[R] t.test() with missing values

[Peter Dalgaard]

Birgit Lemcke wrote:
> Hello!
>
> I am using R 2.5.1 on a Apple Power Book G4 with Mac OS X 10.4.10 and  
> I am still R beginner.
>
> I try to calculate a t.test() using this code:
>
> 	TTest75<-t.test(Fem75, Mal75, alternative= "two.sided", paired= TRUE)
>
> This works properly, but I have two variables with a lot of missing  
> data and therefore get the error message:
>
> 	TTest66<-t.test(Fem66, Mal66, alternative= "two.sided", paired= TRUE)
> 	Fehler in var(x) : 'x' ist leer
>
> One of the two vectors looks like this:
>
> [1] 5.0  NA 4.5 6.0 0.8  NA 7.0 4.5  NA  NA  NA  NA 5.0  NA 6.0  NA  
> 5.0  NA 5.0 8.0  NA  NA  NA 8.0  NA 8.0 5.0  NA  NA  NA  NA 8.0  NA 1.0
> [35]  NA  NA  NA  NA  NA  NA 5.0  NA 4.0 8.0  NA 6.0 6.0 4.5 3.5  NA   
> NA  NA  NA  NA  NA  NA  NA  NA  NA  NA  NA  NA  NA  NA  NA  NA  NA  NA
> [69]  NA  NA  NA  NA  NA  NA  NA  NA  NA  NA  NA  NA  NA  NA  NA  NA ....
>   

> Is it possible to run a TTest inspite of all the missing data?
> I really need two know if may two vectors are significantly  
> different. (If this results are then reliable is an other question)
>   
Well, you're not showing the other one, but I have a hunch that 
any(complete.cases(Fem66, Mal66)) will come out false,  in which case 
you don't have paired data and might get rid of paired=TRUE and have an 
ordinary two sample test. (BTW paired data for females and males? Couples?)


> By the way is there a better possibility (and I guess there is) to  
> save or export the t.test() results as textfile?
>
> Thanks in advance for your help.
>
> Greetings
>
> Birgit
>
> Birgit Lemcke
> Institut für Systematische Botanik
> Zollikerstrasse 107
> CH-8008 Zürich
> Switzerland
> Ph: +41 (0)44 634 8351
> birgit.lemcke at systbot.uzh.ch
>
>
>
>
>
>
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-- 
   O__  ---- Peter Dalgaard             Øster Farimagsgade 5, Entr.B
  c/ /'_ --- Dept. of Biostatistics     PO Box 2099, 1014 Cph. K
 (*) \(*) -- University of Copenhagen   Denmark          Ph:  (+45) 35327918
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