#1
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probability question
40% of people have type O blood, three random people donate blood. Find the probability that exactly one person has type O blood. This is a HMWK problem for me but the teacher didnt explain how to do it [img]/images/graemlins/tongue.gif[/img]
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#2
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Re: probability question
Can you figure the chance of none of them having type O blood?
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#3
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Re: probability question
4 out of 10 people have type O blood. So you divide the possible combinations where 1 and exactly 1 person has type O blood divided by all possible ways to choose 3 people from 10. So the calculation is:
C(4,1)*C(6,2)/C(10,3)=50% Not exactly sure if this is right, but it is my best guess. |
#4
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Re: probability question
[ QUOTE ]
40% of people have type O blood, three random people donate blood. Find the probability that exactly one person has type O blood. This is a HMWK problem for me but I wasn't listening when the teacher explained how to do it [img]/images/graemlins/tongue.gif[/img] [/ QUOTE ] FYP Read this |
#7
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Re: probability question
The question is ambiguous. MickeyHoldem pointed to an explanation if there is an infinite population of people. In that case the answer is 3*0.4*0.6^2 = 42.3%. You answered it assuming the population is 10 people in which case the answer is 50%.
If the population size is N, the answer is: C(0.4*N,1)*C(0.6*N,2)/C(N,3) = 0.4*N*[0.6*N*(0.6*N-1)/2]/[N*(N-1)*(N-2)/6] =0.72*N*(0.6*N-1)/[(N-1)*(N-2)] This goes from a high of 0.6 (N = 5) down to 0.432 as N increases. |
#8
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Re: probability question
[ QUOTE ]
The question is ambiguous. MickeyHoldem pointed to an explanation if there is an infinite population of people. In that case the answer is 3*0.4*0.6^2 = 42.3%. You answered it assuming the population is 10 people in which case the answer is 50%. [/ QUOTE ] Actually it's worse than that - there isn't sufficient information since the population that donates blood is self-selected. |
#9
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Re: probability question
Where do you go to school?
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