Mean absolute errors recorded for subjects at 2 year intervals.

Significance levels calculated using Friedman Test (Nonparametric Repeated Measures ANOVA), post hoc Dunn's Multiple Comparison Test comparing gender groups in Grade 4 and 6 to the corresponding Grade 2 group.

本研究采用弗里德曼检验（Friedman Test，非参数重复测量方差分析）计算显著性水平，并通过事后Dunn多重比较检验（post hoc Dunn's Multiple Comparison Test），将四年级与六年级的性别组别分别与对应的二年级组别进行比较。