Ⅰ 搴锋墭鍒嗗竷鐨勬湡鏈涘拰鏂瑰樊鎬庝箞姹傦紵銆婃傜巼璁哄熀纭鏁欑▼銆嬩範棰
E锛圶n锛=0脳0.5+2脳0.5=1
E锛圶锛=鈭(1~n)E(Xi)/(3^i)=鈭(1~n)1/(3^i)
鈭(1~n)1/(3^i)鏄涓涓绛夋瘮鏁板垪锛屽叕姣1/3,鐢ㄧ瓑姣旀眰鍜屽叕寮忓緱
E(X)=1/2
D(X)=鈭(1~n)D(Xi)/(3^i)²
***VAR琛ㄧず鏂瑰樊锛屾垜涔犳儻鐢―琛ㄧず
D(Xi)=E(Xi²)-(EXi)²
E(Xi²)=4脳0.5=2
D(Xi)=1
D(X)=鈭(1~n)D(Xi)/(3^i)²=鈭(1~n)1/(3^i)²
鈭(1~n)1/(3^i)鏄涓涓绛夋瘮鏁板垪锛屽叕姣1/9,鐢ㄧ瓑姣旀眰鍜屽叕寮忓緱
D(X)=1/8