AFNI program: 3dFDR
Output of -help
Program: 3dFDR
Author: B. Douglas Ward
Initial Release: 31 January 2002
Latest Revision: 31 January 2002
This program implements the False Discovery Rate (FDR) algorithm for
thresholding of voxelwise statistics.
Program input consists of a functional dataset containing one (or more)
statistical sub-bricks. Output consists of a bucket dataset with one
sub-brick for each input sub-brick. For non-statistical input sub-bricks,
the output is a copy of the input. However, statistical input sub-bricks
are replaced by their corresponding FDR values, as follows:
For each voxel, the minimum value of q is determined such that
E(FDR) <= q
leads to rejection of the null hypothesis in that voxel. Only voxels inside
the user specified mask will be considered. These q-values are then mapped
to z-scores for compatibility with the AFNI statistical threshold display:
stat ==> p-value ==> FDR q-value ==> FDR z-score
Usage:
3dFDR
-input fname fname = filename of input 3d functional dataset
OR
-input1D dname dname = .1D file containing column of p-values
-mask_file mname Use mask values from file mname.
Note: If file mname contains more than 1 sub-brick,
the mask sub-brick must be specified!
Default: No mask
-mask_thr m Only voxels whose corresponding mask value is
greater than or equal to m in absolute value will
be considered. Default: m=1
Constant c(N) depends on assumption about p-values:
-cind c(N) = 1 p-values are independent across N voxels
-cdep c(N) = sum(1/i), i=1,...,N any joint distribution
Default: c(N) = 1
-quiet Flag to suppress screen output
-list Write sorted list of voxel q-values to screen
-prefix pname Use 'pname' for the output dataset prefix name.
OR
-output pname
INPUT DATASET NAMES
-------------------
This program accepts datasets that are modified on input according to the
following schemes:
'r1+orig[3..5]' {sub-brick selector}
'r1+orig<100.200>' {sub-range selector}
'r1+orig[3..5]<100..200>' {both selectors}
'3dcalc( -a r1+orig -b r2+orig -expr 0.5*(a+b) )' {calculation}
For the gruesome details, see the output of 'afni -help'.
This page generated on
Tue Aug 3 16:42:45 EDT 2004