> -Original Message-
> From: Mario [mailto:[EMAIL PROTECTED]
> Sent: Monday, August 25, 2008 5:41 PM
> To: Greg Snow
> Cc: r-help@r-project.org
> Subject: Re: [R] Two envelopes problem
>
> Dear Greg,
>
> The problem is that in your code you are creating a
ECTED] On Behalf Of Mark Leeds
> Sent: Tuesday, August 26, 2008 9:44 AM
> To: 'Duncan Murdoch'
> Cc: r-help@r-project.org
> Subject: Re: [R] Two envelopes problem
>
> Hi Duncan: I think I get you. Once one takes expectations,
> there is an underlying assumption abo
Duncan Murdoch wrote:
On 26/08/2008 7:54 AM, Jim Lemon wrote:
Hi again,
Oops, I meant the expected value of the swap is:
5*0.5 + 20*0.5 = 12.5
Too late, must get to bed.
But that is still wrong. You want a conditional expectation,
conditional on the observed value (10 in this case). The a
A very important point is missing here. If there is x in one envelope
and 2x in the other the expected gain is 3x/2. If the idea is to
switch after observing the second envelope the expected gain is again
3x/2. In the case being put x will be either 5 or 10. But x is a
parameter and in this cas
age-
From: Duncan Murdoch [mailto:[EMAIL PROTECTED] Sent: Tuesday,
August 26, 2008 11:26 AM
To: Mark Leeds
Cc: r-help@r-project.org
Subject: Re: [R] Two envelopes problem
On 8/26/2008 9:51 AM, Mark Leeds wrote:
Duncan: I think I see what you're saying but the strange thing is
that if
yo
Mark
-Original Message-
From: Duncan Murdoch [mailto:[EMAIL PROTECTED] Sent: Tuesday,
August 26, 2008 11:26 AM
To: Mark Leeds
Cc: r-help@r-project.org
Subject: Re: [R] Two envelopes problem
On 8/26/2008 9:51 AM, Mark Leeds wrote:
Duncan: I thi
>>> Duncan Murdoch <[EMAIL PROTECTED]> 26/08/2008 16:17:34 >>>
>>If this is indeed the case, switch; the expected gain is
>>positive because _you already have the information that you hold the
>> median value of the three possibilities_. The tendency when
presented
> >with the problem is to reaso
-Original Message-
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
On Behalf Of Duncan Murdoch
Sent: Tuesday, August 26, 2008 05:15
To: Jim Lemon
Cc: r-help@r-project.org; Mario
Subject: Re: [R] Two envelopes problem
On 26/08/2008 7:54 AM, Jim Lemon wrote:
> Hi again,
> Oops, I meant the ex
o: Mark Leeds
Cc: r-help@r-project.org
Subject: Re: [R] Two envelopes problem
On 8/26/2008 9:51 AM, Mark Leeds wrote:
Duncan: I think I see what you're saying but the strange thing is
that if
you use the utility function log(x) rather than x, then the expected
values
are equal.
I think
s because I think I see it now by your example below.
Mark
-Original Message-
From: Duncan Murdoch [mailto:[EMAIL PROTECTED]
Sent: Tuesday, August 26, 2008 11:26 AM
To: Mark Leeds
Cc: r-help@r-project.org
Subject: Re: [R] Two envelopes probl
Mark
-Original Message-
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Duncan Murdoch
Sent: Tuesday, August 26, 2008 8:15 AM
To: Jim Lemon
Cc: r-help@r-project.org; Mario
Subject: Re: [R] Two envelopes problem
On 26/08/2008 7:54 AM, Jim Lemon wrot
to:[EMAIL PROTECTED] On
Behalf Of Duncan Murdoch
Sent: Tuesday, August 26, 2008 8:15 AM
To: Jim Lemon
Cc: r-help@r-project.org; Mario
Subject: Re: [R] Two envelopes problem
On 26/08/2008 7:54 AM, Jim Lemon wrote:
> Hi again,
> Oops, I meant the expected value of the swap is:
>
> 5*0.5
onth a few years
> ago
> and we gave up so it's interesting for me to see this again.
>
>Mark
>
> -Original Message-
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
> On
> Behalf Of Duncan Murdoch
> Sent: Tu
Original Message-
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Duncan Murdoch
Sent: Tuesday, August 26, 2008 8:15 AM
To: Jim Lemon
Cc: r-help@r-project.org; Mario
Subject: Re: [R] Two envelopes problem
On 26/08/2008 7:54 AM, Jim Lemon wrote:
> Hi again,
> Oops, I mea
On 26/08/2008 7:54 AM, Jim Lemon wrote:
Hi again,
Oops, I meant the expected value of the swap is:
5*0.5 + 20*0.5 = 12.5
Too late, must get to bed.
But that is still wrong. You want a conditional expectation,
conditional on the observed value (10 in this case). The answer depends
on the d
Hi again,
Oops, I meant the expected value of the swap is:
5*0.5 + 20*0.5 = 12.5
Too late, must get to bed.
Jim
__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org
Hi Mario,
If I understand your problem statement, the random choice of one of the
two envelopes ensures that the probability of choosing one or the other
is 0.5. If you find 10 (units, I can't find the pound symbol on this
keyboard), there is an equal likelihood that the other envelope contains
5 o
> -Original Message-
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf
> Of Mario
> Sent: Monday, August 25, 2008 1:51 PM
> To: Greg Snow; r-help@r-project.org
> Subject: Re: [R] Two envelopes problem
>
> No, no, no. I have solved the Monty Hall proble
on than what is in the puzzle.
--
Gregory (Greg) L. Snow Ph.D.
Statistical Data Center
Intermountain Healthcare
[EMAIL PROTECTED]
(801) 408-8111
-Original Message-
From: Mario [mailto:[EMAIL PROTECTED]
Sent: Monday, August 25, 2008 2:51 PM
To: Greg Snow; r-help@r-project.org
Subject: Re:
4:35 PM
To: Mario
Cc: r-help@r-project.org; Greg Snow
Subject: Re: [R] Two envelopes problem
On Mon, Aug 25, 2008 at 1:51 PM, Mario <[EMAIL PROTECTED]> wrote:
> No, no, no. I have solved the Monty Hall problem and the Girl's problem and
> this is quite different. Imagine this, I
On Mon, Aug 25, 2008 at 1:51 PM, Mario <[EMAIL PROTECTED]> wrote:
> No, no, no. I have solved the Monty Hall problem and the Girl's problem and
> this is quite different. Imagine this, I get the envelope and I open it and
> it has £A (A=10 or any other amount it doesn't matter), a third friend gets
what is in the puzzle.
--
Gregory (Greg) L. Snow Ph.D.
Statistical Data Center
Intermountain Healthcare
[EMAIL PROTECTED]
(801) 408-8111
> -Original Message-
> From: Mario [mailto:[EMAIL PROTECTED]
> Sent: Monday, August 25, 2008 2:51 PM
> To: Greg Snow; r-help@r-project.org
> S
Sent: Monday, August 25, 2008 1:41 PM
To: r-help@r-project.org
Subject: [R] Two envelopes problem
A friend of mine came to me with the two envelopes problem, I
hadn't heard of this problem before and it goes like this:
someone puts an amount `x' in an envelope and an amount `2x'
in ano
ata Center
Intermountain Healthcare
[EMAIL PROTECTED]
(801) 408-8111
> -Original Message-
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED] On Behalf Of Mario
> Sent: Monday, August 25, 2008 1:41 PM
> To: r-help@r-project.org
> Subject: [R] Two envelopes problem
&g
i haven't looked at your code and I'll try when I have time but, as
you stated, that's an EXTREMELY famous problem that has tried to be
posed
in a bayesian way and all sorts of other things have been done to try
solve it. Note that if you change the utility function so that its
log(X) rather t
A friend of mine came to me with the two envelopes problem, I hadn't
heard of this problem before and it goes like this: someone puts an
amount `x' in an envelope and an amount `2x' in another. You choose one
envelope randomly, you open it, and there are inside, say £10. Now,
should you keep th
26 matches
Mail list logo
