中文说明：
为建立完善的ARMA模型，进行的预处理，包括野点的分离去除，离散傅里叶变换去除周期项，以及正态性、平稳性检验。
English Description：
In order to establish a perfect ARMA model, the pretreatment includes the separation and removal of outliers, the removal of periodic terms by discrete Fourier transform, and the test of normality and stationarity.