2
$\begingroup$

I'm having a problem running a repeated-measures ANOVA in R using the ezANOVA function.

I have data from 20 subjects - each subject participated in 2 conditions and 2 laps (80 total data points in a balanced design with no missing cells).

When I try to run the full RM ANOVA

model<-ezANOVA(data=RMdata
           ,dv=sd_speed
           ,wid=P
           ,within=c("Pr","lap")
           ,type=3)

I get the following error over and over again:

Error in ezANOVA_main(data = data, dv = dv, wid = wid, within = within,  : 
  "dv" must be numeric.

But the dv (sd_speed) is numeric!

Classes ‘grouped_df’, ‘tbl_df’, ‘tbl’ and 'data.frame': 80 obs. of  4 variables:
 $ P       : Factor w/ 20 levels "1","2","3","4",..: 1 2 3 4 5 6 7 8 9 10 ...
     $ Pr      : Factor w/ 2 levels "control","VPA": 1 1 1 1 1 1 1 1 1 1 ...
 $ sd_speed: num  4.06 4.55 3.82 10.96 3.28 ...
     $ lap     : Factor w/ 2 levels "1","2": 1 1 1 1 1 1 1 1 1 1 ...
 - attr(*, "vars")=List of 1
  ..$ : symbol P
 - attr(*, "drop")= logi TRUE

I've read and tried everything and I really don't know how to fix it. It would be a pleasure if someone could help me!

$\endgroup$
4
$\begingroup$

This seems to be a bug associated with the 'tbl_df' format of your data frame. You can turn your data into a standard R data frame by using the function data.frame(). For example, right within the call to ezANOVA:

model<-ezANOVA(data=data.frame(RMdata)
       ,dv=sd_speed
       ,wid=P
       ,within=c("Pr","lap")
       ,type=3)
$\endgroup$
  • $\begingroup$ Great! That was too easy, I should have been able to know this :/. Thanks a lot!! $\endgroup$ – A.L Oct 1 '15 at 0:49

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.