[R] Balanced design throws "design unbalanced, cannot proceed" error

[Bert Gunter]

Inline ...

On Wed, May 22, 2013 at 6:40 AM, Krysta Chauncey
<krysta at essential-design.com> wrote:
> Well spotted.  I've changed that now (it was an artifact from previous
> work), so there's no devicegroup--just device and group, as in the model.
>  So now table(data.AMIDS_d[,2:5]) produces
>
> , , width = fat, length = long
>
>      device
> group Dingo SNAR
>    NR    12   12
>    NV    12   12
>    RA    12   12
>
> , , width = nom, length = long
>
>      device
> group Dingo SNAR
>    NR    12   12
>    NV    12   12
>    RA    12   12
>
> , , width = fat, length = nom
>
>      device
> group Dingo SNAR
>    NR    12   12
>    NV    12   12
>    RA    12   12
>
> , , width = nom, length = nom
>
>      device
> group Dingo SNAR
>    NR    12   12
>    NV    12   12
>    RA    12   12
>
> but print(model.tables(aov.AMIDS_d,"means"),digits=3) still produces the
> same "Error in model.tables.aovlist(aov.AMIDS_d, "means") :  design is
> unbalanced so cannot proceed".
>
> As I'm sure you've gathered, I'm a beginner to R so am certainly missing
> obvious error-checking/debug methods. What's my next step?
>

Learn about error-checking/debug methods -- study the chapter on
Debugging in the R Language Definition Manual.

-- Bert


>
>
> On Tue, May 7, 2013 at 12:28 PM, David Winsemius <dwinsemius at comcast.net>wrote:
>
>>
>> On May 7, 2013, at 8:33 AM, Krysta Chauncey wrote:
>>
>> > I think this means an unequal sample in different conditions. But it
>> seems
>> > to mean something else. . .
>> >
>> > I have a data set like below
>> >
>> > particip    group   device  width   length  accep   thresh  rating
>> > d-rating1           RA      Dingo   nom     nom     Y       5       8
>> >     31           RA      Dingo   nom     long    Y       4       6
>> >   21           RA      Dingo   fat     nom     Y       4       6
>> > 21           RA      Dingo   fat     long    N       6       4
>> > -2
>> >
>> > and I'm running an ANOVA on it like so
>> >
>> > aov.AMIDS_d <- aov(d.rating ~ group*device*width*length +
>> > Error(particip/(device*width*length))+group,data.AMIDS_d)
>> >
>> > This works ok until I try to print the condition means like so
>> >
>> > print(model.tables(aov.AMIDS_d,"means"),digits=3)
>> >
>> > and it says
>> >
>> > Error in model.tables.aovlist(aov.AMIDS_d, "means") : design is
>> > unbalanced so cannot proceed
>> >
>> > According to the design, it ought to be balanced, so I need to check my
>> > data structure. I tried
>> >
>> > table(data.AMIDS_d[,2:5])
>>
>> In this table there is a variable named "devicegroup". In the model there
>> are terms named 'device' and 'group" but none named 'devicegroup'. This
>> error  could have been identified 4 days ago on SO if you had edited the
>> question to include the results of that table operation. It would have been
>> even better to also  offer str(aov.AMIDS_d).
>>
>> --
>> David.
>>
>> >
>> > to give a table of observations per condition and got this
>> >
>> > , , width = fat, length = long
>> >
>> >     devicegroup Dingo SNAR
>> >   NR    12   12
>> >   NV    12   12
>> >   RA    12   12
>> > , , width = nom, length = long
>> >
>> >     devicegroup Dingo SNAR
>> >   NR    12   12
>> >   NV    12   12
>> >   RA    12   12
>> > , , width = fat, length = nom
>> >
>> >     devicegroup Dingo SNAR
>> >   NR    12   12
>> >   NV    12   12
>> >   RA    12   12
>> > , , width = nom, length = nom
>> >
>> >     devicegroup Dingo SNAR
>> >   NR    12   12
>> >   NV    12   12
>> >   RA    12   12
>> >
>> > which looks both correct and balanced. So what am I missing, where's this
>> > error coming from?
>> >
>> >       [[alternative HTML version deleted]]
>> >
>> > ______________________________________________
>> > R-help at r-project.org mailing list
>> > https://stat.ethz.ch/mailman/listinfo/r-help
>> > PLEASE do read the posting guide
>> http://www.R-project.org/posting-guide.html
>> > and provide commented, minimal, self-contained, reproducible code.
>>
>> David Winsemius
>> Alameda, CA, USA
>>
>>
>
>         [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.



-- 

Bert Gunter
Genentech Nonclinical Biostatistics

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