EEG

The multiple comparison problem In neuroimaging analysis one often is confronted with many electrodes/voxels and many timepoints, and often performs a statistical test on each of these electrode/timepoint combinations. This leads to a massive multiple comparison problem, as the probability to find a false positive is greatly enhanced. In the following example we assume independence of all data points . For instance with only 10 electrodes/voxels and 10 timepoints and an alpha of 0.05, the probability for a false positive is: $$ p(significance^*|H_0) = 1-(1-0.05)^{10*10}=99.4 $$ *significance of at least one sample But electrodes/voxels and timepoints usually are not independent….