# stat question

• Feb 28th 2009, 11:36 AM
NidhiS
stat question
An oil exploration company currently has two active projects, one in Asia and theother in Europe. Let A be the event that the Asian project is successful and B be the eventthat the European project is successful. Suppose that A and B are independent eventswith P(A)=0.4 and P(B)=0.7.
a. If the Asian project is not successful, what is the probability that the European projectis also not successful? Explain your reasoning.
b. What is the probability that at least one of the two projects will be successful?
c. Given that at least one of the two projects is successful, what is the probability thatonly the Asian project is successful?

I could actually do part a and b and I got .3 for a and .82 for part b.I don't know how to go about part c (Worried)
• Feb 28th 2009, 02:36 PM
mr fantastic
Quote:

Originally Posted by NidhiS
An oil exploration company currently has two active projects, one in Asia and theother in Europe. Let A be the event that the Asian project is successful and B be the eventthat the European project is successful. Suppose that A and B are independent eventswith P(A)=0.4 and P(B)=0.7.
a. If the Asian project is not successful, what is the probability that the European projectis also not successful? Explain your reasoning.
b. What is the probability that at least one of the two projects will be successful?
c. Given that at least one of the two projects is successful, what is the probability thatonly the Asian project is successful?

I could actually do part a and b and I got .3 for a and .82 for part b.I don't know how to go about part c (Worried)

c) requires conditional probability.

Calculate Pr(only A | at least one success) = Pr(only A and at least one success)/Pr(at least one success) = Pr(only A and at least one success)/0.82.

Can you calculate Pr(only A and at least one success)?
• Feb 28th 2009, 06:24 PM
NidhiS
[HTML]Can you calculate Pr(only A and at least one success)?[/HTML]

Is that P(AB' and (A U B)) because it's says only A. is that good?
• Feb 28th 2009, 07:09 PM
mr fantastic
Quote:

Originally Posted by NidhiS
[html]Can you calculate Pr(only A and at least one success)?[/html]

Is that P(AB' and (A U B)) because it's says only A. is that good?

I'm not sure what you're asking but if you draw a tree diagram, getting Pr(only A and at least one success) from it should not be too difficult .... I get (0.4)(0.3)
• Feb 28th 2009, 07:21 PM
NidhiS
I get the same answer I guess,

P(AB' and (A U B)) = P(AB') I used the venn diagram.So If something's in A and not in B and we AND it with what's in A and B then the common region is the region Of A that doesn't include B which is the same as AB'(Nod)

which is (0.4) *(0.3)

Thanks
• Feb 28th 2009, 07:23 PM
mr fantastic
Quote:

Originally Posted by NidhiS
I get the same answer I guess,

P(AB' and (A U B)) = P(AB') I used the venn diagram.So If something's in A and not in B and we AND it with what's in A and B then the common region is the region Of A that doesn't include B which is the same as AB'(Nod)

which is (0.4) *(0.3)

Thanks

I hope you haven't forgotten that the final answer will be 0.12/0.82 = ....
• Feb 28th 2009, 07:26 PM
NidhiS
no I didn't.(Giggle)