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【单选题】
正态分布 N( μ,σ 2) ,当 μ恒定时,σ 2 越大A.
曲线沿横轴越向左移动
B.
曲线沿横轴越向右移动
C.
观察值变异程度越大，曲线越“胖”
D.
观察值变异程度越小，曲线越“瘦”
E.
曲线形状和位置不变
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参考解析：
知识点：
皮皮学刷刷变学霸
举一反三
【单选题】关于光纤通信系统设计,正确的是( )。
A.
检测器选取应在光源选取之后。
B.
损耗受限系统是当系统的带宽很大且对系统的影响可以忽略时，中继距离由发送端到接收端之间的光通道损耗决定。
C.
色散受限系统是当系统的光通道损耗很大且传输速率很大时，中继距离由发送端到接收端之间的色散决定。
D.
波分系统常选用G.655光纤，工作波长为1310窗口。
【单选题】There are six people in the office. ____ of them are party members.
A.
All
B.
Both
C.
No one
D.
Neither
【简答题】光源的作用是什么?光纤通信系统中常用的光源主要有哪两类?
【简答题】填空 1. His family _____ （be）very big. There are six people. 2. My family _____ (be) very well.
【单选题】There are six people, ______ three women.
A.
includes
B.
include
C.
including
D.
included
【简答题】There are six people present at the meeting, ( ) three women.
【单选题】There are six people present at the meeting, ____ three women.
A.
include
B.
including
C.
included
D.
includes
【简答题】完形填空（本题有10小题，每小题1分，共10分） My name is Tony. I have a big . There are six people in family. They are my grandfather, my grandmother, my , my sister and I. I don’t have any brothers. I am a at a school in...
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