结果表明三因素模型结构不稳定，但短期比长期结构稳定性要高；大部分组合回归系数时序稳定性较差，同时ARMA和GARCH模型对每个回归系数时间序列进行预测显示有较好的预测能力。

The results show that the model is instability in the long run, most coefficient is non-stationary, and we can preferably forecast the coefficient by using the ARMA, GARCH model.

youdao

结果表明三因素模型结构不稳定，但短期比长期结构稳定性要高；大部分组合回归系数时序稳定性较差，同时ARMA和GARCH模型对每个回归系数时间序列进行预测显示有较好的预测能力。

The results show that the model is instability in the long run, most coefficient is non-stationary, and we can preferably forecast the coefficient by using the ARMA, GARCH model.

youdao