作者sunnypace (蝸牛)
看板Statistics
標題[問題] 一題關於機率的問題
時間Mon Nov 9 00:37:32 2009
想請問大家一題機率的問題
Researchers determined that children under 2 years old who sleep with
the lights on have a 36% chance of becoming myopic before they are 16。
Children who sleep in darkness have a 21% probability of becoming myopic。
A survey indicates that 28% of children under 2 sleep with some light on。
Find the probability that a child under 16 ismyopic。
答案是0.2520
想了很久~還是算不出來@@
那部份主要講樹狀圖
麻煩大家了~
謝謝!!!!!!!!
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◆ From: 60.198.2.129
1F：推 ksherry:0.36*0.28 + 0.21*0.72 11/09 05:52
2F：→ sunnypace:謝謝樓上幫忙!!^^ 11/09 22:38