Re: [FRIAM] Fwd: FlowingData - Best statistics question ever

2011-10-29 Thread Robert J. Cordingley 

Here's how I'd analyze/state it.

It all revolves around the first 'if' statement.  If I choose an answer 
at random then I can't let any information from that answer influence my 
result or it wont be random.  Since there are 4 choices and now I can't 
pay attention to what they are, then at random each has an equal 
probability.  A 25% B 25% C 25% D 25%.  So given enough tries that's how 
the results would distribute.  But two of the answers are the same so I 
have a 50% chance of choosing the answer represented by A or D which are 
clearly now the wrong answer - they don't match.  I have a 25% chance of 
choosing B which also doesn't match and C doesn't match anything.  So 
the chance of being correct is 0%.


Robert C

On 10/29/11 8:27 AM, Victoria Hughes wrote:



Best statistics question ever 



Posted: 28 Oct 2011 01:25 AM PDT

Best Math Question EVAR 



By way of Raymond Johnson 
, 
the best statistics multiple choice question ever written on a 
chalkboard. Try not to think too hard. [via 
]


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Re: [FRIAM] Fwd: FlowingData - Best statistics question ever

2011-10-29 Thread Russ Abbott 
For Russ Standish, the question is
here.
And here's my plodding answer.

If 25% were the correct answer, then either (a) or (d) would be right. So
one would have a 50% chance of getting the correct answer. Hence 25% is not
the correct answer.

If 50% were the correct answer, then (b) would be right. But then one would
have only a 25% chance of picking it by chance. So 50% is not the correct
answer.

If one allowed either 25% or 50% as the correct answer, then 75% would be
the correct answer since (a), (b), or (d) would be correct.

The joke should be that (c) reads 75% rather than 60%. In that case (d)
would be the correct answer. Hence any answer would be correct and one
would have a 100% chance of getting the correct answer.

But none of the answers is 100%. So the correct answer is 0%.

If as John suggests (d) were 0%, then if we decide that neither 25% nor 50%
is the correct answer. then (d) is the correct answer. But in that case,
one would have a 25% chance of getting the correct answer, etc.

On the other hand, the above could be taken to show that none of the
suggested answers is correct.  With (c) at 60%, that seems to be a
reasonable conclusion. So pick any answer and one will be certain to be
wrong. But since none of the answers offers that probability, any selection
will be consistent with that result. Of course there is no way to select
that answer from the ones given. But if there were, as we saw when we
allowed (d) to be 0%, that would foul that answer up anyway.

*-- Russ *



On Sat, Oct 29, 2011 at 2:30 PM, Russell Standish wrote:

> What was the question?
>
> On Sat, Oct 29, 2011 at 08:27:35AM -0600, Victoria Hughes wrote:
> > >Best statistics question ever
> > >Posted: 28 Oct 2011 01:25 AM PDT
> > >
> > >
> > >By way of Raymond Johnson, the best statistics multiple choice
> > >question ever written on a chalkboard. Try not to think too hard.
> > >[via]
> > >
> > >
> > >You are subscribed to email updates from FlowingData
> > >To stop receiving these emails, you may unsubscribe now. Email
> > >delivery powered by Google
> > >Google Inc., 20 West Kinzie, Chicago IL USA 60610
> >
>
> > 
> > FRIAM Applied Complexity Group listserv
> > Meets Fridays 9a-11:30 at cafe at St. John's College
> > lectures, archives, unsubscribe, maps at http://www.friam.org
>
>
> --
>
>
> 
> Prof Russell Standish  Phone 0425 253119 (mobile)
> Principal, High Performance Coders
> Visiting Professor of Mathematics  hpco...@hpcoders.com.au
> University of New South Wales  http://www.hpcoders.com.au
>
> 
>
> 
> FRIAM Applied Complexity Group listserv
> Meets Fridays 9a-11:30 at cafe at St. John's College
> lectures, archives, unsubscribe, maps at http://www.friam.org
>

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Re: [FRIAM] Fwd: FlowingData - Best statistics question ever

2011-10-29 Thread Russell Standish 
What was the question?

On Sat, Oct 29, 2011 at 08:27:35AM -0600, Victoria Hughes wrote:
> >Best statistics question ever
> >Posted: 28 Oct 2011 01:25 AM PDT
> >
> >
> >By way of Raymond Johnson, the best statistics multiple choice
> >question ever written on a chalkboard. Try not to think too hard.
> >[via]
> >
> >
> >You are subscribed to email updates from FlowingData
> >To stop receiving these emails, you may unsubscribe now. Email
> >delivery powered by Google
> >Google Inc., 20 West Kinzie, Chicago IL USA 60610
> 

> 
> FRIAM Applied Complexity Group listserv
> Meets Fridays 9a-11:30 at cafe at St. John's College
> lectures, archives, unsubscribe, maps at http://www.friam.org


-- 


Prof Russell Standish  Phone 0425 253119 (mobile)
Principal, High Performance Coders
Visiting Professor of Mathematics  hpco...@hpcoders.com.au
University of New South Wales  http://www.hpcoders.com.au



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