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WONKOW (WONKOW) 于 (Thu Dec 6 13:57:47 2007) 提到:
given x1 ... x10 are iid.
can you have std(x)=0? --- easy one.
can you have std(x)=10? --- sure you can.
can you say anything about positiveness of x1...x10? like are they all
positive or negative?
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Jadeson (Jadeson) 于 (Thu Dec 6 15:20:12 2007) 提到:
Morningstar的一道面试题。
不能。
算算total variance的最大值就可以了。
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zzoren (zzoren) 于
