
Advanced Statistics Advanced Probability and Statistics Math Forum 
 LinkBack  Thread Tools  Display Modes 
October 15th, 2011, 02:08 AM  #1 
Newbie Joined: Sep 2011 Posts: 29 Thanks: 0  probability, train stops
A train transports 15 passengers through seven stops. each passenger has equal probability to leave on any of these seven stops and passengers act irrespective of each other  passengers are independent, not couples or married. train stops if someone gets off. What is the probability that no one gets off on first stop? I assume, that probability that someone gets off on some stop is 1/7 and after that 6/7. 1  1/7 = 6/7 And 15 * 6/7 = 12 6/7 = 0.12855 
October 15th, 2011, 11:49 AM  #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: probability, train stops
Why do you multiply by 15? That gives a number which clearly isn't a probability (not in the range of 0 to 1). You want to raise to the power of 15.

October 16th, 2011, 12:34 AM  #3 
Newbie Joined: Sep 2011 Posts: 29 Thanks: 0  Re: probability, train stops
Yes, range must be 0 to 1. I assume, that probability that someone gets off on some stop is 1/7 and after that 6/7. 1  1/7 = 6/7 = 0,86 And 0.86^15 / 7 = 0.01487 
October 17th, 2011, 03:38 AM  #4 
Newbie Joined: Sep 2011 Posts: 29 Thanks: 0  Re: probability, train stops
Hello. Is my solution correct?

October 18th, 2011, 01:52 AM  #5 
Newbie Joined: Sep 2011 Posts: 29 Thanks: 0  Re: probability, train stops
I will try again. Can someone answer this, please. I'm just searching a probability that someone gets off on first stop. I assume, that probability that someone gets off on some stop is 1/7 and after that 6/7. 1  1/7 = 6/7 = 0,86 And 0.86^15 / 7 = 0.01487 Maybe this is needed: 1/7 * 2/7 * 3/7 * 4/7 * 5/7 * 6/7 * + 0.01487 ... I don't know, but maybe solution is very near. 
October 19th, 2011, 10:43 AM  #6 
Newbie Joined: Sep 2011 Posts: 29 Thanks: 0  Re: probability, train stops
Hi. Can someone please help. I have really tried to solve and I don't know what a correct solution is. ( I'm afraid that my solution is not correct ).

October 19th, 2011, 04:52 PM  #7  
Math Team Joined: Dec 2006 From: Lexington, MA Posts: 3,267 Thanks: 407  Re: probability, train stops Hello, mike688! Quote:
For each passenger:[color=beige] .[/color][color=beige] .[/color] at each stop. We want the probability that all 15 passengers "stay" on the first stop.  
October 20th, 2011, 01:22 AM  #8 
Newbie Joined: Sep 2011 Posts: 29 Thanks: 0  Re: probability, train stops
Thanks a lot! I got confused... Ah, it was just like that. I was close. Now I understand it. Really great that you ( both ) helped.


Tags 
probability, stops, train 
Thread Tools  
Display Modes  

Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
probability set theory  probability of x out of n events  hbonstrom  Applied Math  0  November 17th, 2012 08:11 PM 
interference of two wave train  Chikis  Physics  2  August 16th, 2012 10:27 PM 
A train of 3000 KN  rsoy  Physics  11  June 10th, 2012 02:27 PM 
Joint probability density function, probability  token22  Advanced Statistics  2  April 26th, 2012 04:28 PM 
Probability (probability mass function,pmf)  naspek  Calculus  1  December 15th, 2009 02:18 PM 