推 playmypig :應該是(1/2)^x for x=2,3,4,5,...吧? 04/25 19:28
→ playmypig :不好意思,看漏了"equal"一字 04/25 19:29
Let X equal the number of flips of a fair coin that are required to oberserved
head-tails on consecutive flips.
Find the p.m.f of X (hint: Draw a tree diagram)
ans: f(x)=(x-1)/2^x ,x=2.3.4....
我怎麼畫樹狀圖 機率都跟他給的答案不同....?
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