需要的数学技能 极大似然估计:https://www.zhihu.com/question/24124998 关于数据属于何种分布的回答: 大数定律:https://www.zhihu.com/question/19911209/answer/876481176 梯度下降:https://www.zhihu.com/question/305638940/answer/670034343