s***k
发帖数: 33 | 1 10 coins with probabilities of 1, 1/2, 1/3,...,1/10 of coming up
heads are flipped. What is the probability that an odd number of them
come up heads? | F****z
发帖数: 12 | | s***k
发帖数: 33 | 3 能解释一下吗？
【在 F****z 的大作中提到】
: 1/2
| g**********l
发帖数: 9 | 4 hint: second coin (what if you flip it?)
【在 s***k 的大作中提到】
: 能解释一下吗？
| s***k
发帖数: 33 | 5 second coin heads up chance 1/2, then?
【在 g**********l 的大作中提到】
: hint: second coin (what if you flip it?)
| m********s
发帖数: 8 | 6 The second coin is special.
By conditioning on all other coins, we get
1/2 * p + 1/2 *(1-p)= 1/2.
It doesn't matter what p is.
that 1/2 ruins (or saves) everything. | s***k
发帖数: 33 | 7 got it, thanks, as long as there is one coin with 1/2, answer is the same.
【在 m********s 的大作中提到】
: The second coin is special.
: By conditioning on all other coins, we get
: 1/2 * p + 1/2 *(1-p)= 1/2.
: It doesn't matter what p is.
: that 1/2 ruins (or saves) everything.
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