Drexel dragonThe Math ForumDonate to the Math Forum



Search All of the Math Forum:

Views expressed in these public forums are not endorsed by Drexel University or The Math Forum.


Math Forum » Discussions » sci.math.* » sci.math

Topic: Conditional Probability Question
Replies: 49   Last Post: Oct 18, 2001 2:34 PM

Advanced Search

Back to Topic List Back to Topic List Jump to Tree View Jump to Tree View   Messages: [ Previous | Next ]
mensanator

Posts: 5,039
Registered: 12/6/04
Re: Conditional Probability Question
Posted: Sep 26, 2001 9:40 AM
  Click to see the message monospaced in plain text Plain Text   Click to reply to this topic Reply



>Subject: Re: Conditional Probability Question
>From: Virgil vmhjr2@home.com
>Date: 9/25/01 11:23 PM Central Daylight Time
>Message-id: <vmhjr2-DECB08.22331625092001@news1.denver1.co.home.com>
>
>In article <20010925234846.05795.00000711@mb-mf.aol.com>,
> mensanator@aol.com (Mensanator) wrote:
>

>> >Subject: Re: Conditional Probability Question
>> >From: Ray Vickson rvickson@engmail.uwaterloo.ca
>> >Date: 9/25/01 5:09 PM Central Daylight Time
>> >Message-id: <3BB10091.36487FAB@engmail.uwaterloo.ca>
>> >
>> >There is a difference between examining previous parts and not examining
>> >them. If you take out (i-1) parts and put them aside without examining
>> >them, the probability that the i'th part (which IS examined) will be
>> >defective is 1/100. Surprisingly, this is true even if i=100, so you are
>> >drawing from a box that contains only 1 part. However, everything
>> >changes if the set-aside parts are examined instead of ignored.

>>
>> Why does it change?

>
>One's evaluation of probability is generally dependent on one's
>state of knowledge at the time of the evaluation. Each part
>examined, up to finding the defective part, changes one's state of
>knowledge.


I don't see that. What changes is that on every inspection, the probabilty of
finding the part goes from 1/100 to 1/1. But that is _not_ the probability that
the part is _at_ position i. It is the probability of finding it at postion i
_combined_ with the probability that it is _not_ at posititions i-1. And if you
do the correct math, you'll see that this is 1/100 for every i.

And the probability the ith part is defective does not change based on your
knowledge of the previous i-1 inspections, so it doesn't matter whether you
inspect them or not.






Date Subject Author
9/25/01
Read Conditional Probability Question
Aaron Davies
9/25/01
Read Re: Conditional Probability Question
Wade Ramey
9/25/01
Read Re: Conditional Probability Question
Randy Poe
9/25/01
Read Re: Conditional Probability Question
Aaron Davies
9/26/01
Read Re: Conditional Probability Question
Kevin Foltinek
9/26/01
Read Re: Conditional Probability Question
mensanator
9/27/01
Read Re: Conditional Probability Question
Kevin Foltinek
9/27/01
Read Re: Conditional Probability Question
Aaron Davies
9/27/01
Read Re: Conditional Probability Question
mensanator
9/25/01
Read Re: Conditional Probability Question
Steve Wright
9/25/01
Read Re: Conditional Probability Question
Timothy E. Vaughan
9/26/01
Read Re: Conditional Probability Question
Lionel Barnett
9/25/01
Read Re: Conditional Probability Question
Virgil
9/25/01
Read Re: Conditional Probability Question
Ray Vickson
9/25/01
Read Re: Conditional Probability Question
mensanator
9/26/01
Read Re: Conditional Probability Question
Virgil
9/26/01
Read Re: Conditional Probability Question
mensanator
9/26/01
Read Re: Conditional Probability Question
Virgil
9/27/01
Read Re: Conditional Probability Question
mensanator
9/27/01
Read Re: Conditional Probability Question
The Scarlet Manuka
9/27/01
Read Re: Conditional Probability Question
mensanator
9/27/01
Read Re: Conditional Probability Question
Virgil
9/27/01
Read Re: Conditional Probability Question
Aaron Davies
9/28/01
Read Re: Conditional Probability Question
mensanator
9/26/01
Read Re: Conditional Probability Question
Ray Vickson
9/26/01
Read Re: Conditional Probability Question
mensanator
9/27/01
Read Re: Conditional Probability Question
Virgil
9/27/01
Read Re: Conditional Probability Question
mensanator
9/27/01
Read Re: Conditional Probability Question
mensanator
9/27/01
Read Re: Conditional Probability Question
Virgil
9/28/01
Read Re: Conditional Probability Question
mensanator
9/28/01
Read Re: Conditional Probability Question
Virgil
9/28/01
Read Re: Conditional Probability Question
David Lloyd-Jones
9/28/01
Read Re: Conditional Probability Question
mensanator
9/29/01
Read Re: Conditional Probability Question
David Lloyd-Jones
9/29/01
Read Re: Conditional Probability Question
mensanator
9/29/01
Read Re: Conditional Probability Question
David Lloyd-Jones
9/29/01
Read Re: Conditional Probability Question
mensanator
9/29/01
Read Re: Conditional Probability Question
David Lloyd-Jones
9/29/01
Read Re: Conditional Probability Question
mensanator
9/29/01
Read Re: Conditional Probability Question
Virgil
9/29/01
Read Re: Conditional Probability Question
mensanator
9/29/01
Read Re: Conditional Probability Question
Lynn Kurtz
9/27/01
Read Re: Conditional Probability Question
Aaron Davies
9/27/01
Read Re: Conditional Probability Question
mensanator
9/27/01
Read Re: Conditional Probability Question
Virgil
10/17/01
Read Re: Conditional Probability Question
Mike Mccarty Sr
10/18/01
Read Re: Conditional Probability Question
Virgil
9/27/01
Read Re: Conditional Probability Question
Randy Poe
9/25/01
Read Re: Conditional Probability Question
mensanator

Point your RSS reader here for a feed of the latest messages in this topic.

[Privacy Policy] [Terms of Use]

© Drexel University 1994-2014. All Rights Reserved.
The Math Forum is a research and educational enterprise of the Drexel University School of Education.