Re: Oneway Anova from a covariance/cross-product matrix?

[John Darrington]

Thanks, I see that now.

However I think this is going to become an unmitigated nuisance.
We can't always be sure that the dependent variable will be the last
row/column  and I see that there is code in the fill_covariance function
in regression.q which rearranges the matrix to satisfy this condition.

I suggest that instead, we change reg_sweep so that it accepts an integer
which is the index of the row/column of the dependent variable.  This 
would be simple to implement using gsl_matrix_swap_rows/gsl_matrix_swap_columns.

J'

On Wed, Jul 07, 2010 at 11:25:32AM -0400, Jason Stover wrote:
     On Tue, Jul 06, 2010 at 07:09:05PM +0000, John Darrington wrote:
     > So what exactly do we pass to reg_sweep ?
     > 
     > Passing M doesn't seem to help.  If we need to use g or x then that 
     > requires access to the raw data.  I understood that anova could be 
calculated 
     > from M alone.
     
     Almost: reg_sweep expects the final column and row to contain the values 
related to
     the dependent variable. So it should work with
     
         g1           x
     g1  1.5          3.0
     x   3.0          16.0
      
     Also, that matrix doesn't contain information related to the
     intercept, or "grand mean," meaning you would need to either include
     such a column in your covariance matrix, or call
     post_sweep_computations.
     

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