
Advanced Statistics Advanced Probability and Statistics Math Forum 
 LinkBack  Thread Tools  Display Modes 
February 13th, 2010, 04:39 AM  #1 
Newbie Joined: Feb 2010 Posts: 3 Thanks: 0  fair coin tossing, and choosing directions.
I was reading up some introductory discrete probability to use in analyzing randomized algorithms, and I was trying to solve this problem, but couldn't quite nail it. Your city is planned in the form of an infinite grid of crossings. You start from your house, and walk aimlessly. You have a fair coin with you, which you toss to find out which direction to go. You can't turn and walk back, so at each junction you have three choices of direction(front, left, right). Describe a method(give an experiment involving coin tossing) which would let you choose each direction with an equal probability of 1/3. My idea is to toss the coin twice, and decide as follows : if you get 2 heads go left, if a tail and a head, then go straight, if a head and a tail, then go right(the order in which you get head and tail matters). If you get two tails, then toss again. Can someone tell me if this is right?(Is there a better solution?) Or any other ideas about how to approach this problem? Thanks in advance! 
February 13th, 2010, 12:23 PM  #2  
Global Moderator Joined: Nov 2006 From: UTC 5 Posts: 16,046 Thanks: 938 Math Focus: Number theory, computational mathematics, combinatorics, FOM, symbolic logic, TCS, algorithms  Re: fair coin tossing, and choosing directions. Quote:
 
February 14th, 2010, 04:30 AM  #3 
Newbie Joined: Feb 2010 Posts: 3 Thanks: 0  Re: fair coin tossing, and choosing directions.
Thanks! I'm post a better solution/analysis if I find one.

February 14th, 2010, 04:31 AM  #4 
Newbie Joined: Feb 2010 Posts: 3 Thanks: 0  Re: fair coin tossing, and choosing directions.
Thanks! I'll post a better solution/analysis if I find one. (sorry for the typo in the last post!)

February 14th, 2010, 01:20 PM  #5  
Global Moderator Joined: May 2007 Posts: 6,730 Thanks: 689  Re: fair coin tossing, and choosing directions. Quote:
 

Tags 
choosing, coin, directions, fair, tossing 
Thread Tools  
Display Modes  

Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
A Fair Coin  Chikis  Advanced Statistics  11  October 15th, 2012 10:02 AM 
coin tossing bias  baxy7  Advanced Statistics  5  July 3rd, 2011 09:34 AM 
Coin tossing  nikov  Algebra  3  April 28th, 2009 03:32 AM 
Coin tossing  krackwacker  Advanced Statistics  5  November 6th, 2008 07:17 PM 
a game of coin tossing  aptx4869  Advanced Statistics  4  April 6th, 2007 02:07 PM 