Hi all,
Was hoping one of you could help me wrap my mind around the below;
presuming B occurs, the probability that A occurs is AnB/B
Thank you,
g3lo
Probability Help
This topic has expert replies
- GMATinsight
- Legendary Member
- Posts: 1100
- Joined: Sat May 10, 2014 11:34 pm
- Location: New Delhi, India
- Thanked: 205 times
- Followed by:24 members
Yes you are right... It's conditional probability. You can read in detail as Baye's theorem/Conditional probability.g3lo wrote:Hi all,
Was hoping one of you could help me wrap my mind around the below;
presuming B occurs, the probability that A occurs is AnB/B
Thank you,
g3lo
"GMATinsight"Bhoopendra Singh & Sushma Jha
Most Comprehensive and Affordable Video Course 2000+ CONCEPT Videos and Video Solutions
Whatsapp/Mobile: +91-9999687183 l [email protected]
Contact for One-on-One FREE ONLINE DEMO Class Call/e-mail
Most Efficient and affordable One-On-One Private tutoring fee - US$40-50 per hour
Most Comprehensive and Affordable Video Course 2000+ CONCEPT Videos and Video Solutions
Whatsapp/Mobile: +91-9999687183 l [email protected]
Contact for One-on-One FREE ONLINE DEMO Class Call/e-mail
Most Efficient and affordable One-On-One Private tutoring fee - US$40-50 per hour
GMAT/MBA Expert
- [email protected]
- Elite Legendary Member
- Posts: 10392
- Joined: Sun Jun 23, 2013 6:38 pm
- Location: Palo Alto, CA
- Thanked: 2867 times
- Followed by:511 members
- GMAT Score:800
Hi g3lo,
Conditional probability is exceptionally rare on the GMAT (I'll bet that you don't see it at all on the Official GMAT). In the event that you see a Quant question that 'hints' at conditional probability, you will almost certainly be able to answer the question using simpler probability concepts and/or permutations or combinations.
GMAT assassins aren't born, they're made,
Rich
Conditional probability is exceptionally rare on the GMAT (I'll bet that you don't see it at all on the Official GMAT). In the event that you see a Quant question that 'hints' at conditional probability, you will almost certainly be able to answer the question using simpler probability concepts and/or permutations or combinations.
GMAT assassins aren't born, they're made,
Rich
- DavidG@VeritasPrep
- Legendary Member
- Posts: 2663
- Joined: Wed Jan 14, 2015 8:25 am
- Location: Boston, MA
- Thanked: 1153 times
- Followed by:128 members
- GMAT Score:770
The concept is more important than the derivation of the notation. (And, thankfully, the concept really isn't complicated, at least for what we'll need on the GMAT.)g3lo wrote:Hi all,
Was hoping one of you could help me wrap my mind around the below;
presuming B occurs, the probability that A occurs is AnB/B
Thank you,
g3lo
Imagine you have a bag of marbles. There are 3 red and 5 blue marbles and no other kinds of marbles. Say we select two marbles at random and we want to know the probability that we select two red marbles.
The scenario when we select a red marble on the first pick, we'll call: Event A
The scenario when we select a red marble on the second pick, we'll call: Event B
First, find P(A): There are 3 red marbles and 8 total marbles, so P(A) = 3/8
Next find P(B|A): The notation here simply means the probability that B will occur, given that A has occurred. So if A occurred, then we selected a red marble with the first pick. In this case, there will be 2 red marbles remaining and 7 total marbles remaining, meaning that P(B|A) = 2/7.
And the probability that we select a red on both picks is P(A) * P(B|A) = (3/8) * (2/7)
The most important thing is to make sure you note that the composition of the bag's marbles changes with each selection. (When you're solving this on your own, you don't need to use the notation.)
GMAT/MBA Expert
- [email protected]
- Elite Legendary Member
- Posts: 10392
- Joined: Sun Jun 23, 2013 6:38 pm
- Location: Palo Alto, CA
- Thanked: 2867 times
- Followed by:511 members
- GMAT Score:800
Hi g3lo,
I've responded to your PM; if you have any additional questions, then you can feel free to contact me directly (by email or by PM).
GMAT assassins aren't born, they're made,
Rich
I've responded to your PM; if you have any additional questions, then you can feel free to contact me directly (by email or by PM).
GMAT assassins aren't born, they're made,
Rich