[R] Manova question.
Douglas Bates
bates at wisc.edu
Tue Jun 15 19:11:25 CEST 2004
Jens Schumacher wrote:
> knussear wrote:
>
>> Hi list,
>>
>> I'm attempting to re-create a Repeated Measures Compositional Analysis as
>> described in the work by Aebischer et. al. (Ecology. 1993. 74(5):
>> 1313-1325).
>>
>> In this paper they describe transitions of data into a log ratio
>> difference matrix, from which they obtain two matrices using a monova
>> routine.
>>
>> I am able to produce the second of the two matrices, but I'm having
>> trouble with the first.
>>
>> the difference matrix going in is given here.
>>
>> Animal Scrub Bl wood Con wood Grass
>> 1 0.970 -2.380 -5.154 -9.408
>> 2 1.217 -0.173 -4.955 -5.521
>> 3 1.178 -0.248 -4.089 0.338
>> 4 0.520 0.466 -4.801 -1.946
>> 5 8.445 9.319 10.753 8.171
>> 6 8.654 9.327 10.732 8.152
>> 7 8.429 9.350 10.818 8.141
>> 8 9.120 9.565 3.813 8.127
>> 9 9.227 9.882 3.813 7.779
>> 10 9.423 8.086 3.813 8.539
>> 11 9.626 9.392 3.813 8.135
>> 12 9.234 8.302 3.813 8.537
>> 13 8.672 8.908 9.832 8.416
>>
>>
>> And the first of the matrices is given here, and is "matrix of
>> mean-corrected sums of squares and cross products calculated from the
>> difference matrix."
>>
>>
>> Scrub Bl wood Con wood Grass
>> Scrub 179.52 214.59 244.58 273.75
>> Bl wood 214.59 268.44 314.35 343.86
>> Con wood 244.58 314.35 471.09 400.22
>> Grass 273.75 343.86 400.22 477.78
>>
>>
>> From manova on the data set I can get the diagonal of the matrix, but
>> not the others.
>>
>> manova(y ~ NULL)
>>
>> Terms:
>> Residuals
>> Scrub 179.5273
>> Bl.wood 268.4347
>> Con.wood 471.0845
>> Grass 477.8014
>> Deg. of Freedom 12
>>
>>
>> Could anyone offer a suggestion ?
>>
>> Thanks
>>
>>
>> Ken
>>
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>>
>>
> Let data.matrix be the above difference matrix. You obtain the "raw
> sums of squares and cross-products matrix" by
>
> R2 <- t(data.matrix) %*% data.matrix
>
> or even
> R2 <- crossprod(data.matrix, data.matrix)
or, the preferred form,
R2 <- crossprod(data.matrix)
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