a fair dice is thrown and then a fair coin is tossed a number of times equal to the number shown on the dice.find the probrablity of obtaining no head given that the number on the dice is 4 or 5
THXXXXXXX
MATH probability一題!!!!!!!THXX
2011-10-19 4:10 am
回答 (3)
2011-10-19 7:47 am
✔ 最佳答案
When the die is 4Probability of no head
= (1/2)^4
= 1/16
When the die is 5
Probability of no head
= (1/2)^5
= 1/32
As the probability of getting 4 or 5 is equal, the required probability
= (1/2)(1/16 + 1/32)
= 3/64
2011-10-19 23:36:39 補充：
因為已經給了骰子的數字是4或5﹐因此是1/2而不是1/6
2011-10-28 4:35 am
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2011-10-27 20:36:57 補充：
die is 4
= (1/2)^4
= 1/16
die is 5
= (1/2)^5
= 1/32
= (1/2)(1/16 + 1/32)
= 3/64
2011-10-27 20:36:57 補充：
die is 4
= (1/2)^4
= 1/16
die is 5
= (1/2)^5
= 1/32
= (1/2)(1/16 + 1/32)
= 3/64
2011-10-19 6:45 am
**No headappears = tail appears**P(head)= P(tail) = 0.5 , P (1 or 2 or 3 or 4 or 5 or 6) = 1/6P(nohead|no. is 4) + P(no head|no. is 5)= P(tail|no. is 4) + P( tail|no. is 5)= P(tail∩no. is 4)/P(no.is 4) + P(tail∩no. is 5)/P(no. is 5)= ((0.5)^4x (1/6)) / (1/6) + ((0.5)^5 x (1/6)) / (1/6)=(0.5)^4+ (0.5)^5=0.09375
參考: ME!
收錄日期: 2021-04-13 18:18:26
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https://hk.answers.yahoo.com/question/index?qid=20111018000051KK00706