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å-amean: Estimates the mean for every level of factor ÔaÕ (collapsed across factor ÔbÕ) and provides a t-statistic for the null hypothesis, Ho: mean = 0
íIn this example, the mean percent signal change for each stimulus condition type is averaged across subjects on a voxel-by-voxel basis
íFor example:
í
í Mean Percent Signal Change at Voxel ÒxÓ
í
í             Subject (b)
í ED EE EF
í TM 4.1% 3.8% 4.5%  Þ M = 4.13%
íStim Cond (a) HM 3.2% 2.5% 2.8%  Þ M = 2.83%
í TP 4.6% 4.1% 4.9%  Þ M = 4.53%
í HP 1.7% 2.0% 1.1%  Þ M = 1.60%
í
í
íAllows you to determine if the percent signal change in a voxel is significantly different from zero.  If so, appears as colored activation  blobs