问题
填空题
假设随机变量X在[-1，1]上服从均匀分布，a是区间[-1，1]上的一个定点，Y为点X到a的距离，当a=______时，随机变量X与Y不相关．
答案
参考答案：0
解析： 已知
EX=0，依题意Y=|X-a|，a应使EXY=EXEY=0，其中
令EXY=
(a2-3)=0，解得a=0，(a=
舍去)．
搜题请搜索小程序“爱下问搜题”
假设随机变量X在[-1，1]上服从均匀分布，a是区间[-1，1]上的一个定点，Y为点X到a的距离，当a=______时，随机变量X与Y不相关．
参考答案：0
解析： 已知
EX=0，依题意Y=|X-a|，a应使EXY=EXEY=0，其中
令EXY=
(a2-3)=0，解得a=0，(a=
舍去)．
填空:从方框中选择恰当的单词或短语填入句子中,注意使用其正确形式.
2. We need to learn to accept people who have different _________. 3. After a heated discussion at the meeting, a new plan _________. 4. I'm glad you _______ the mistake before it was too late. 5. The program is _______ every Monday evening. 6. He has been asked to _______ his absence. 7. People _______ too much importance ______ economic forecasts. 8. Thousands of people ________ for the rock concert last Sunday. 9. He ___________ and in a couple of weeks my beautiful, shiny bicycle was ready. 10. After _________ each other for several minutes, the two men began to fight fiercely. 11. Children have a natural ________ about the world around them. 12. The child ought to be punished. You shouldn't let him _________ telling lies. |