table of contents
LIPSIA     Statistical comparison of two groups
vpaired_ttest
This program performs a paired t-test between two groups of contrast images. The number of images in the two groups must match. The ouput is a tmap or a zmap that gives the statistical significance of a pairwise difference between the two groups.

vpaired_ttest -in1 cgtbsm_group1_*.v -in2 cgtbsm_group2_*.v -out zmap.v

Positive values in the output map indicate that the mean values in group 1 ('-in1') are larger than mean values in group 2 ('-in2'). In line with the LIPSIA convention when determining contrasts, negative values indicate that mean group 1 < mean group 2.

Caution: Make sure that the files in the two groups are listed in the correct order. If wildcards ("*") are used, the programs will order them alphabetically. Also note that the program 'vpaired_ttest' should only be used on registered data, i.e. on data that are geometrically aligned and normalized.

Parameters of 'vpaired_ttest':
-help
Prints usage information.
-in1
Input files of 1st group. Default: (none)
-in2
Input files of 2nd group. Default: (none)
-type [ tmap | zmap ]
Type of output. Default: zmap
-out
Output file. Default: (none)


Max Planck Institute for Human Cognitive and Brain Sciences. Further Information: lipsia@cbs.mpg.de
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