boredsatan
Member
- Joined
- Mar 23, 2017
- Messages
- 572
- Gender
- Male
- HSC
- 1998
Is "nor" the same as "and" in probability?
The second one is always correct. The first is only correct if Pr(A and B) = 0 (basically mutually exclusive events).P(a u b) = P(a) + P(b)
P(a u b) = P(a) + P(b) - P(a and b)
which formula is correct?
I see both formulas being used in calculations
If P(Sally alive) = 0.8 and P(Peter NOT alive) = 0.3,There are two friends, peter and sally. Their respective probabilities of being alive in 40 years time are 0.7 and 0.8. What is the probability that Sally is alive in 40 years time, given that one of them is alive then?
No problemboredofsatan, just 2 friendly reminders...
1. It may be helpful for you to demonstrate what you understand in terms of the concepts, maybe show working or attempts on the question. This is to give other users assurance/evidence, that they are not just for instance doing your homework etc. for you, and that you are actually learning and grappling with the concepts.
2. Also, do not excessive bump your question if it hasn't been answered yet. (and sometimes you come across as "swamping" with lots of questions, ask one or two at a time)
thanks
dan
If you use the second formula for P(A and B), is that wrong?The second one is always correct. The first is only correct if Pr(A and B) = 0 (basically mutually exclusive events).
It's not wrong (as I said, the second is always correct).If you use the second formula for P(A and B), is that wrong?
Thanks
The answer said 24/38. Do you now how it's worked out?If P(Sally alive) = 0.8 and P(Peter NOT alive) = 0.3,
Then the probability that only Sally is alive in 40 years time is given by
P(Sally alive) x P(Peter NOT alive) = 0.8 x 0.3 = 0.24
ThanksIt's not wrong (as I said, the second is always correct).
You need to make an assumption about the dependence of the lives, otherwise there is not enough information to do the question. Since we aren't told anything about it, you probably should assume the lives are independent.There are two friends, peter and sally. Their respective probabilities of being alive in 40 years time are 0.7 and 0.8. What is the probability that Sally is alive in 40 years time, given that one of them is alive then?
You need to use the definition of conditional probability and make an independence assumption. See my above post.The answer said 24/38. Do you now how it's worked out?
Yep-y≥ - x + 2
y≤1x - 2
Are these the same?
Yep remember that dividing or multiplying by a negative swaps the sign-y≥ - x + 2
y≤1x - 2
Are these the same?
I guarantee you boredsatan will not follow these. __________this is planned. He will follow these rules to prove me wrong.boredofsatan, just 2 friendly reminders...
1. It may be helpful for you to demonstrate what you understand in terms of the concepts, maybe show working or attempts on the question. This is to give other users assurance/evidence, that they are not just for instance doing your homework etc. for you, and that you are actually learning and grappling with the concepts.
2. Also, do not excessive bump your question if it hasn't been answered yet. (and sometimes you come across as "swamping" with lots of questions, ask one or two at a time)
thanks
dan
we will give him the benefit of the doubt...I guarantee you boredsatan will not follow these. __________this is planned. He will follow these rules to prove me wrong.
§§§
Can you please stop the insultsI guarantee you boredsatan will not follow these. __________this is planned. He will follow these rules to prove me wrong.
§§§