Leo tosses 3 coins once in a certain game. Suppose tossing the coins to obtain 3heads gets an award of 50 coupons,2 heads gets 10coupons,2head gets 10coupons,1head gets 5 coupons but getting no head will lose 100 coupons.
Find the
a)probabilities that Leo gets 3heads,2heads and 1 head
b)the ecpected value of award he can get in one game
one f.3 probability question
2011-11-20 11:14 pm
回答 (3)
2011-11-20 11:17 pm
✔ 最佳答案
(a) P(3 heads) = 1/2 * 1/2 * 1/2 = 1/8
P(2 heads) = 3 * 1/2 * 1/2 * 1/2 = 3/8
P(1 heads) = 3 * 1/2 * 1/2 * 1/2 = 3/8
P(0 heads) = 1/2 * 1/2 * 1/2 = 1/8
(b) Expected value
= 50 * 1/8 + 10 * 3/8 + 5 * 1/8 - 100 * 1/8
= -15/8
2011-12-01 1:00 pm
那位expected value錯了... 3/8寫成1/8...
2011-11-21 12:43 am
a)
P(3Heads)=1/2*1/2*1*2=1/8
P(2Heads)=3/8
P(1Head)=3/8
P(no Heads)=1/8
b)
the expected value
=50*1/8+10*3/8+5*3/8-100*1/8
=6.25+3.75+1.875-12.5
=-5/8
P(3Heads)=1/2*1/2*1*2=1/8
P(2Heads)=3/8
P(1Head)=3/8
P(no Heads)=1/8
b)
the expected value
=50*1/8+10*3/8+5*3/8-100*1/8
=6.25+3.75+1.875-12.5
=-5/8
收錄日期: 2021-04-26 19:16:59
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https://hk.answers.yahoo.com/question/index?qid=20111120000051KK00487