As Hurst parameter estimated bias exists, the precision may be improved by using non-linear estimate, where ARFIMA model is proposed and used for verification.

• 从统计结果来看，样本序列呈现出尖峰、胖尾等有偏特征，明显不满足正态分布的假设，表明收益序列可能具有长程相关或记忆性。