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Abstract #2863

Jackknife Assessment of Individual Subject Effects on a Mixed-Effect Group Level fMRI Analysis

Chilakamarri Venkat P, Oakes T, Alexander A, Johnstone T
University of Wisconsin-Madison, University of Wisconsin-Madison

This study used a jackknife statistical analysis to quantify theimpact of intrasubject effect magnitude and variance on the group T-statistic in mixed effects linear model. Data weredrawn from 40 subjects who performed arapid event related task (Go/Nogo). A linear predictor forthe change in T-statistic upon dropping a single subject from theanalysis yielded R-squared = 0.69 when using the subjectsestimated effect magnitude and standard deviation, and R-squared= 0.89 when using their quotient. Even with this large group, individualsubjects caused changes in T-values of as much as 12%