Two Plus Two Newer Archives  

Go Back   Two Plus Two Newer Archives > General Gambling > Probability
FAQ Community Calendar Today's Posts Search

Reply
 
Thread Tools Display Modes
  #1  
Old 10-08-2007, 09:32 AM
Ncoe Ncoe is offline
Member
 
Join Date: Jul 2007
Posts: 53
Default Just a weird thought

Say there's a game where u get to pick one of four options, A,B,C or D where one of them gets you a point.

For each time u play you get exact probabilities for the separate options being the correct one.
Such as, A=50%, B=35%, C=10% and D=5%.
Obviously it's an easy choice to go with the option that has the highest probability for being correct.

But say you instead use some sord of randomizer to choose your pick, but with the corresponding probabilities.

So that in this example, you would on average pick option A 50% of the time, B 35% of the time etc.

Would this be equal resultwise to always picking the one with the highest probability?
Reply With Quote
  #2  
Old 10-08-2007, 09:57 AM
sixhigh sixhigh is offline
Senior Member
 
Join Date: Oct 2005
Location: Highway 61
Posts: 1,778
Default Re: Just a weird thought

<font color="#FF4444">[*] </font> Let's make this easy. Two options, A and B. A wins with probability p and B with 1-p. wolog p&gt;0.5. If you always choose A you win with probability p.

if you choose A with probaility p and B with probability (1-p) we have four cases:
1. (A, A, p*p) you choose A and A wins: probability p*p
2. (A, B, p*(1-p))
3. (B, A, (1-p)*p)
4. (B, B, (1-p)(1-p))

You win in case 1 and 4 - which is gonna happen with the probability p*p + (1-p)(1-p) = 1-2p+2p^2.

And 1-2p+2p^2&lt;p for every p in (0.5, 1).

This also holds true in a general case with more options.
Reply With Quote
Reply


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 11:33 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.