how to find difference from the measurement of all genes at the same time point

I have a problem that i have just worked out the measurement of a gene and the corresponding mean of this gene. I now have been asked to subtract this difference from the measurements of all the genes i have above at the same time point. Any ideas on how i enter this code into matlab?

[Alamanda Ponappa Poovaya]

Hi,

It would be helpful if you could share the code you currently have at the moment