10,000 times, and the null distribution of test statistics was obtained for the group difference. Finally, the proportion of sampled permutations where the t-values were greater than the observed test statistic was calculated as the p-value of the observed group difference. A level of significance was set p < 0.05 (uncorrected), and participant's age, gender, and IQ were used as covariates to remove potential biases to the statistical result.
