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macau1111 2017-10-6 04:46 AM

Applied maths 問題

HKALE Applied Maths 1997 Paper ll Q6
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[attach]7414197[/attach]
紅圈點解係0?
藍圈點解可以由x1,x2變做x?
請師兄指教

ppresent 2017-10-6 11:14 PM

x1 and x2 have the same distribution with mean mu:
E(x1)=E(x2)=mu,
I think this should answer all your questions

macau1111 2017-10-8 10:11 PM

Alternative solution 1 & 2 都明白
不過[E(x1-x2)]^2=0都係唔明白
同埋問題嘅2個random variables 相減嘅expected value 有咩meaning?

ppresent 2017-10-9 08:57 PM

E(x1-x2)=E(x1)-E(x2)
You may find more about what expected value means from wiki
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查看完整版本: Applied maths 問題