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February 28, 2014 02:42PM
Hi guys,

I have a quick question about fdrval:

I generated a brik dataset using 3dANOVA2 and trying to compute a t-value given a q-value using fdrval:

fdrval -qinput results_anova+tlrc 1 0.01

The sub-brik for the t-stat is 1 and the input for the q-value is 0.01. fdrval returns 5.144 and this value does not change even if the q-value is set to 0.001.

Looking at the AFNI GUI, there are no voxels that pass the q=0.01 threshold and it looks like that 5.144 is the t-value for the voxel with the smallest p-value. The q-value does not change passed 0.0353.

I'm using this in a script that creates "maps' for different q-values and this behavior causes my script to report significant regions at q=0.01 even though they do not pass this threshold, because the t-value reported by fdrval is used for thresholding.

So here is my question, finally:
Would it be possible to calculate the t-value for a given q-value, even though there is no voxel in the dataset that passes this threshold and return that value instead? Or would it be possible to return a t-value that is very high instead?

Thanks!
Jonathan
Subject Author Posted

fdrval: ceiling effect for given q-value

jlisinski February 28, 2014 02:42PM

Re: fdrval: ceiling effect for given q-value

gang March 04, 2014 11:02AM

Re: fdrval: ceiling effect for given q-value

jlisinski March 12, 2014 05:35PM

Re: fdrval: ceiling effect for given q-value

Emperor Zhark March 13, 2014 09:33AM

Re: fdrval: ceiling effect for given q-value

Emperor Zhark March 14, 2014 09:11AM

Re: fdrval: ceiling effect for given q-value

jlisinski March 17, 2014 01:06PM