[R] data transformation

[David L Carlson]

I don't think you have given us enough information. For example, is the 500x500 matrix a distance matrix or does it represent 500 columns of information about 500 rows of observations? If a distance matrix, how is distance being measured? You clarification suggests it may be a distance matrix of correlation coefficients? If distance has different meanings between -1 and 0 and 0 and +1, getting interpretable results from cluster analysis will be difficult, but it is not clear what you mean by that.

-------------------------------------------------
David L. Carlson
Department of Anthropology
Texas A&M University

-----Original Message-----
From: R-help [mailto:r-help-bounces using r-project.org] On Behalf Of Adrian Johnson
Sent: Sunday, January 20, 2019 8:02 AM
To: r-help <r-help using r-project.org>
Subject: [R] data transformation

Dear group,
My question, perhaps is more of a statistical question using R
I have a data matrix ( 400 x 400 normally distributed) with data
points ranging from -1 to +1..
For certain clustering algorithms, I suspect the tight data range is
not helping resolving the clusters.

Is there a way to transform the data something similar to logit, where
I dont lose normality of the data and yet I can better expand the data
ranges.

Thanks
Adrian

______________________________________________
R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
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


-----Original Message-----
From: R-help [mailto:r-help-bounces using r-project.org] On Behalf Of Adrian Johnson
Sent: Sunday, January 20, 2019 10:08 AM
To: r-help <r-help using r-project.org>
Subject: Re: [R] data transformation

I apologize,  I forgot to mention another key operation.
in my matrix -1 to <0 has a different meaning while values between >0
to 1 has a different set of meaning.  So If I do logit transformation
some of the positives becomes negative (values < 0.5 etc.). In such
case, the resulting transformed matrix is incorrect.

I want to transform numbers ranging from -1 to <0   and numbers
between >0 and 1 independently.

Thanks

______________________________________________
R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
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.