1
姒傜巼璁轰笌鏁扮悊缁熻锛堢浜岀増
.
鍒樺缓浜氾級涔犻瑙ｇ瓟鈥斺�旂鍥涚珷
4
锛?/p>
1
瑙ｏ細
E
(
X
)
=
1
麓
0.25
+
2
麓
0.4
+
3
麓
0.2
+
4
麓
0.1
+
5
麓
0.05
=
2.3
4
锛?/p>
2
瑙ｏ細
鐢?/p>
D
(
X
)
=
E
(
X
2
)
-
[
E
(
X
)]
2
寰?/p>
4
锛?/p>
3
瑙ｏ細
E(X)=0.3003
锛?/p>
E(X
2
)=0.4086
锛?/p>
D(X)=0.3184
锛?/p>
[
D(X)]
1/2
=0.5643
銆?/p>
4
锛?/p>
4
瑙ｏ細
E
(
X
*
)
=
E
X
-
E
(
X
)
=
1
E
[
X
-
E
(
X
)]
=
1
[
E
(
X
)
-
E
(
X
)]
=
0
D
(
X
)
D
(
X
)
D
(
X
)
2
D
(
X
*
)
=
E
(
X
*
)
2
-
[
E
(
X
*
)]
2
=
E
(
X
*
)
2
=
E
X
-
E
(
X
)
=
1
E
[
X
-
E
(
X
)]
2
=
1
D
(
X
)
=
1
D
(
X
)
D
(
X
)
D
(
X
)
4
锛?/p>
5
瑙ｏ細
+楼
1
x
E
(
X
)
=
-楼
xf
(
x
)
dx
=
-
1
p
1
-
x
2
dx
=
0
E
(
X
2
)
=
-+楼楼
x
2
f
(
x
)
dx
=
-
11
p
1
x
-
2
x
2
dx
=
01
p
21
x
-
2
x
2
dx
E(X)
E(X
2
)
D(X)
X
1
50
2501
1
X
2
50
2502
2
鈭?/p>
D(X
1
)
<
D
(X
2
)
锛?/p>
鐢ㄧ敳娉曟祴瀹氱殑绮惧害楂樸�?/p>
X
0
1
2
3
P
0.75
0.2045
0.0409
0.0045