In article <mailman.856.1138295171.29584.bio-soft at net.bio.net>,
Nel N. (sent by Nabble.com) <eeneling at yahoo.com> wrote:
>>hi-i'm a modelling(math) student and are working on cancer predictions
>which uses biology dataset-so i dun quite hav biology
>knowledge-however,the dateset i'm working on which was obtained from
>Affymetrix chip(micrarray technology), it contained genes expressions
>values which include positive and negative values-i've tried searching
Positive and negative values imply that you are looking at log ratios.
Beyond that you must talk to the data providers.