常用函数的期望和方差 连续函数的期望: \ue00d\ue036\ue012\ue037 \ue02c \ue00a\ue01a\ue017\ue036\ue01a\ue037\ue021\ue024\ue022\ue024\ue015\ue01a 离散函数的期望: \ue00d\ue036\ue012\ue037 \ue02c \ue035 \ue01a\ue025\ue019\ue025\ue025\ue023\ue01f\ue024 ① 泊松分布(Poisson) \ue012~π\ue036\ue01c\ue037 \ue00d\ue036\ue012\ue037 \ue02c \ue01c ② 均匀分布\ue012~\ue011\ue036\ue013, \ue014\ue037 \ue00d\ue036\ue012\ue037 \ue02c \ue014 \ue02a \ue0132 ③ 二点分布\ue0320—1\ue033分布\ue00f\ue038\ue012 \ue02c 1\ue039 \ue02c \ue019 \ue00d\ue036\ue012\ue037 \ue02c \ue019 ④ 二项分布\ue012~\ue00e\ue036\ue018, \ue019\ue037 \ue00d\ue036\ue012\ue037 \ue02c \ue018\ue019 ⑤ 高斯分布\ue012~\ue00e\ue036\ue01d, \ue01e\ue020\ue037 \ue00d\ue036\ue012\ue037 \ue02c \ue01d ⑥ 指数分布 f\ue036x\ue037 \ue02c \ue02f1\ue01b\ue016\ue027\ue028\ue029,0,\ue01a \ue02e 0\ue01a \ue02d 0 \ue00d\ue036\ue012\ue037 \ue02c \ue01b 连续函数的方差: \ue00c\ue036\ue012\ue037 \ue02c \ue034\ue03a\ue012 \ue02b \ue00d\ue036\ue012\ue037\ue03b\ue020\ue021\ue024\ue022\ue024\ue017\ue036\ue01a\ue037\ue015\ue01a 离散函数的方差: \ue00c\ue036\ue012\ue037 \ue02c \ue035\ue03a\ue01a\ue025\ue02b \ue00d\ue036\ue012\ue037\ue03b\ue020\ue019\ue025\ue025\ue023\ue01f\ue024 \ue00c\ue036\ue012\ue037 \ue02c \ue01c \ue00c\ue036\ue012\ue037 \ue02c\ue036\ue014 \ue02b \ue013\ue037\ue02012 \ue00c\ue036\ue012\ue037 \ue02c \ue019\ue0361 \ue02b \ue019\ue037 \ue00c\ue036\ue012\ue037 \ue02c \ue018\ue019\ue0361 \ue02b \ue019\ue037 \ue00c\ue036\ue012\ue037 \ue02c \ue01e\ue020 \ue00c\ue036\ue012\ue037 \ue02c \ue01b\ue020 下面的是以前计算方差的公式: : \ue010\ue020\ue02c1\ue018\ue03a\ue036\ue01a\ue01f\ue02b \ue01a\ue037\ue020\ue02a \ue036\ue01a\ue020\ue02b \ue01a\ue037\ue020\ue02a \ue00b \ue02a \ue036\ue01a\ue026\ue02b \ue01a\ue037\ue020\ue03b \ue02c1\ue018\ue030\ue036\ue01a\ue01f\ue020\ue02a \ue01a\ue020\ue020\ue02a \ue00b \ue02a \ue01a\ue026\ue020\ue037 \ue02b \ue018\ue01a\ue020\ue031 \ue02c1\ue018\ue03a\ue01a\ue01f\ue020\ue02a \ue01a\ue020\ue020\ue02a \ue00b \ue02a \ue01a\ue026\ue020\ue03b \ue02b \ue01a\ue020