Fmripower was introduced in the 2007 OHBM Poster. New versions will incorporate all of the techniques described in the paper Power Calculations for Group fMRI, which is in NeuroImage (2008 Jan 1;39(1):261-8).
Who can use fmripower?The GUI should work on all computer platforms, but it currently has only been tested on Linux/Unix and Macs. Matlab and SPM5 (or higher) are required. FSL users working in Windows will need cygwn, but this is a requirement for FSL, so if you're using FSL you already have it.
How can I get fmripower?You can download the latest version.
How do I use fmripower?First download and unzip the fmripower.tgz file and then follow the instructions found here.
How can I get help with fmripower?If you find any bugs, need help, or have suggestions for future versions email firstname.lastname@example.org.
Can fmripower be used for posthoc power analysis?Nope. Sorry, power anlayses are only valid for calculating power for future data analyses. See The Abuse of Power: The Pervasive Fallacy of Power Calculations for Data Analysis John M. Hoenig, Dennis M. Heisey The American Statistician, Vol. 55, No. 1 (Feb., 2001), pp. 19-24 for some interesting examples why posthoc power doesn't make sense. If you are interested in evaluating a study that has already been done, the best thing to do is look at the percent change threshold. Tom Nichols has some documentation on
|© 2011 Jeanette Mumford|