Hello everyone,

i have a question regarding the sampling process in boot().

I try to bootstrap F-values for a repeated measures ANOVA to get a confidence interval of F-values. Unfortunately, while the aov works fine, it fails in the boot()-function. I think the problem might be that the resampling process fails to select both lines of data representing the 2 measuring times for one subject and I therefore get missing cases.

The data is organised like this:
subject ort        mz       PHQ
1          1          1          x
1          1          2          y
2          1          1          z
2          1          2          zz
...


Is there any way to specify, that both lines need to be selected?


Thanks a lot!
Felix Fischer

P.S. If you need to have a look to my code:

F_values <- function(formula, data, indices) {
    d <- data[indices,] # allows boot to select sample
    fit=aov(formula,data=d) #fit model
    return(c(summary(fit)[1][[1]][[1]]$`F value`, summary(fit)[2][[1]][[1]]$`F value`)) #return F-values
   }

   results <- boot(data=anova.daten, statistic=F_values,
      R=10, formula=PHQ_Sum_score~mz*ort+Error(subject/mz))


Dipl. Psych. Felix Fischer

Medizinische Klinik mit Schwerpunkt Psychosomatik
Charité -- Universitätsmedizin Berlin
Luisenstr. 13a
10117 Berlin

Tel.: 030 - 450 553575
Email: felix.fischer@charite.de<mailto:felix.fischer@charite.de>


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