Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
Probability Formula Question
#1
I know and understand that:

P(B|A) = P(AandB)/P(A)

but does...

P(A|B) always = (PAandB)/P(B) as well?

Thanks!
We have a great group of "academic counselors" on this board. You will never find a greater group of supporters willing to offer you the benefit of their experience, helpful advice, and constructive criticism.

Don't miss out on something great just because it might also be difficult.

Road traveled: AA > BS > MSPM (2016)

If God hadn't been there for me, I never would have made it. Psalm 94:16-19
Reply
#2
AND...is this ALWAYS true regardless of whether the events are dependent or independent?

P(AandB) = P(A|B) * P(B) = P(B|A) * P(A)
We have a great group of "academic counselors" on this board. You will never find a greater group of supporters willing to offer you the benefit of their experience, helpful advice, and constructive criticism.

Don't miss out on something great just because it might also be difficult.

Road traveled: AA > BS > MSPM (2016)

If God hadn't been there for me, I never would have made it. Psalm 94:16-19
Reply
#3
Wait, I think I get it.

If the events are independent, then P(AandB) = P(A) * P(B)

If the events are dependent, then P(AandB) = P(A/B) * P(B)

Is that right? I sure hope so. Sad
We have a great group of "academic counselors" on this board. You will never find a greater group of supporters willing to offer you the benefit of their experience, helpful advice, and constructive criticism.

Don't miss out on something great just because it might also be difficult.

Road traveled: AA > BS > MSPM (2016)

If God hadn't been there for me, I never would have made it. Psalm 94:16-19
Reply
#4
Quote:P(B|A) = P(AandB)/P(A)

P(A|B) always = P(AandB)/P(B)

This is correct. The numerator is always P(AandB) for Bayes Theorem. The denominator is the probability which the outcome depends on (tip: it's always the alphabet on the right hand).

P(A|B) can be defined as the probability of A happening on the condition that B happens.
Reply
#5
In regards to your first post, keep in mind that A and B are just random variables. They could represent any number and thus are interchangable
Edit: I just realized that this post was from over a month ago. Whoops! thought it was only a few days old
Reply


Possibly Related Threads...
Thread Author Replies Views Last Post
  Question of college algebra inertia2018 3 440 05-02-2019, 07:30 PM
Last Post: dfrecore
  SL Accounting Question Mab81 3 537 07-06-2018, 08:10 PM
Last Post: Mab81
  Time and Distance question CLEP101 5 997 03-22-2018, 12:37 PM
Last Post: bluebooger
  IC Flashcard Question gnat1001 2 933 05-03-2017, 05:08 PM
Last Post: sanantone
  Statistics Question re: Mean soliloquy 6 1,154 08-04-2014, 01:31 PM
Last Post: Jonathan Whatley
  Principles of Finance sample question from TESC - which formula to use? OfficerA 0 644 07-20-2014, 08:34 PM
Last Post: OfficerA
  APA Citation question JanusthePhoenix 5 1,786 12-03-2009, 03:04 AM
Last Post: JanusthePhoenix
  Microeconomics CLEP question? MCunningham 0 1,320 06-30-2009, 11:00 PM
Last Post: MCunningham
  Probability ACoile 2 1,349 10-14-2008, 05:28 AM
Last Post: ACoile
  Loans, Part 3, Question 14 mstcrow5429 3 1,685 06-28-2007, 10:59 AM
Last Post: Matymus

Forum Jump:


Users browsing this thread: 1 Guest(s)