Mixed models on sample age.

Linear mixed effect models were used to investigate the effects of specimen age on the same independent variables. The models were constructed with specimen and tissue matrix as random factors while specimen age in years was fixed factor. (XLSX)本研究采用线性混合效应模型（Linear mixed effect models），探究样本年龄对同一组自变量的影响。模型以样本与组织基质作为随机因子，将以年为单位的样本年龄设置为固定因子。（XLSX）