Dear Matt,

Thanks very much for that quick and helpful reply -- I had wondered about doing what you suggested, but had thought perhaps I could 'cut out the middleman' of the imputed datasets and pull the matrices directly from Amelia. Clearly not, so now I know how to go forward. 

Many thanks and best wishes

Chris


At 02:08 17/08/2015, Matt Blackwell wrote:
Hi Chris,

There is no way to get those covariance matrices from R directly, but you could calculate them from the imputed datasets and then average the quantities together using the Rubin rules to produce estimates of the covariance matrices and means. These imputed datasets are in the original scales, so this should produce what you are looking for.

Cheers,
Matt

On Fri, Aug 14, 2015 at 4:39 AM Chris McManus <i.mcmanus@ucl.ac.uk> wrote:
Hi -- I am new to this list, have tried searching for an answer on
the existing posts, and don't think there is one already, but
apologies if I have missed it.

My primary interest is in the estimated means and covariances from
the EM procedure (and bootstrapping helps as I need standard errors
of means, covariances, etc).  It is clear that covMatrices and mu are
not on the original scale, and the JSS paper says on page 36 that
"they refer to the variables after being transformed, centered and scaled".

The question is therefore, How do it get them on the original scale?
Is there a transformation matrix somewhere? Do I just alter the means
and SDs back to the original  raw values, or has there been a
rotation of some sort as well?  For my purposes I do need to know the
values on the raw scale measures.  I guess I am missing something
here but am not sure what it is.

Many thanks!

Chris McManus
University College London

--
Amelia mailing list served by HUIT
[Un]Subscribe/View Archive: http://lists.gking.harvard.edu/?info=amelia
More info about Amelia: http://gking.harvard.edu/amelia
Amelia mailing list
Amelia@lists.gking.harvard.edu

To unsubscribe from this list or get other information:

https://lists.gking.harvard.edu/mailman/listinfo/amelia