My Math Forum  

Go Back   My Math Forum > College Math Forum > Advanced Statistics

Advanced Statistics Advanced Probability and Statistics Math Forum


Reply
 
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
mike688 is offline  
 
October 15th, 2011, 11:49 AM   #2
Global Moderator
 
CRGreathouse's Avatar
 
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.
CRGreathouse is offline  
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
mike688 is offline  
October 17th, 2011, 03:38 AM   #4
Newbie
 
Joined: Sep 2011

Posts: 29
Thanks: 0

Re: probability, train stops

Hello. Is my solution correct?
mike688 is offline  
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.
mike688 is offline  
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 ).
mike688 is offline  
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:
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.[color=beige] .[/color]Train stops if someone gets off.
What is the probability that no one gets off on first stop?

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.



soroban is offline  
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.
mike688 is offline  
Reply

  My Math Forum > College Math Forum > Advanced Statistics

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 r-soy 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





Copyright © 2018 My Math Forum. All rights reserved.