[BioC] one-sided (was: expression status from pvalues)

[Kevin R. Coombes]

I can easily think of a reason for a one-sided test.  Consider the case 
where I have copy number data and gene expression data on a bunch of 
samples, and I'd like to test whether changes in gene expression go the 
same direction as changes in copy number.

On 7/11/2012 8:21 AM, James W. MacDonald wrote:
> Hi Alyaa,
>
> On 7/11/2012 2:59 AM, Alyaa Mahmoud wrote:
>> Hi All
>>
>> Is there a way to determine expression status of a gene (up, down) from
>> corrected p.values ?
>
> No. The p-values are strictly between 0 and 1, so there is no way to 
> discern the sign of the underlying t-statistic. This would not be true 
> if you were doing a one-sided t-test, but I can't imagine a use case 
> for a one-sided t-test in the context of microarray analysis.
>
> Best,
>
> Jim
>
>
>>
>> Thanks a lot
>> Alyaa
>>
>