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Overcoming the Perception Problem
Porcus
post Oct 26 2012, 18:35
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Here you got two apparent statistical issues – well assuming the article is to be believed: http://www.guardian.co.uk/world/2012/oct/2...l-sweden-murder . Case in brief: convicted for several murders without much more evidence than confessions; in many cases the prosecution even did argue then that his confessions were indeed reliable (he was, after all, insane).

Prosecution claimed that Berwall had provided information that only the police and the murderer could know about. Let us disregard the claims that he could indeed pick it up in the newspaper, and let us interpret “know about” as “guess without knowing”. Arguing by the infinite monkey theorem, he could of course have guessed sufficiently close, given a large number of attempts.
Had this been a listening test, it would have been the fallacy of reporting only your positives. Either on a single pair to be ABXed – or, alternatively, going to hydrogenaudio with the one nice ABX log out of a hundred.
(I suggested a partial foobar2000 fix against this: http://www.hydrogenaudio.org/forums/index....showtopic=96006 )

Consider then Bergwall's claim that he could guess the right answer out of leading questions.
That's lack of blinding. The test administrator is biased, he wants to have his product sold, and the listener can tell from the grin of his face that this time, X = his expensive product.


--------------------
One day in the Year of the Fox came a time remembered well
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onlyconnect
post Dec 1 2012, 15:16
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QUOTE (item @ Oct 19 2012, 18:33) *
OK: I'll stop worrying about being chatted up, and concentrate on worrying about the incoming ad hominem. Although, to keep my options open - in case you're just cheekily playing hard to get - I'm a 43-year old Gemini vegetarian: mainly single, with a good sense of humour and a two-bedroom flat in a nice part of South London. I'm not representing anyone: I like music, I think how we listen is interesting. I'm not presenting myself as an authority. I think it's important not to ignore facts, and to be impartial when reasoning from inferences.


Umm, I know you on another forum as a trade member under the name "Item audio". Is that not relevant?

Tim
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Arnold B. Kruege...
post Dec 2 2012, 01:21
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QUOTE (Porcus @ Oct 26 2012, 12:35) *
Consider then Bergwall's claim that he could guess the right answer out of leading questions.


Seems like a very believable claim.

Further light would be shed by a critical review of a recording of the interrogation.

QUOTE
That's lack of blinding. The test administrator is biased, he wants to have his product sold, and the listener can tell from the grin of his face that this time, X = his expensive product.


No further effort need be expended to support a claim that single blind tests are very likely to be compromised. It is an accepted fact.

Making listening evaluations double blind is usually easy enough. If there is any doubt, simply redo the evaluation as a DBT.

This post has been edited by Arnold B. Krueger: Dec 2 2012, 01:22
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jaythesail
post Dec 2 2012, 01:43
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If I may include a side note to the discussion...

As a rather average punter I have a lot of respect for those who continually (and usually politely) hold the fort against the continual onslaught of misinformation, bad logic and just plain bs. To the regulars - I salute you.

For myself and my few audio enthusiast friends, ABX testing on showing whether A is better than B isn't so significant. It is the ABX testing showing there is no difference that is more important. We know that there isn't some next higher level of musical enjoyment that we are missing out on because we haven't invested mega bucks into cables, conditioning sprays or whatever else someone might want to sell. Clarity to cut through the BS and focus on the simple stuff that matters.
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Arnold B. Kruege...
post Dec 2 2012, 14:05
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QUOTE (jaythesail @ Dec 1 2012, 19:43) *
If I may include a side note to the discussion...

As a rather average punter I have a lot of respect for those who continually (and usually politely) hold the fort against the continual onslaught of misinformation, bad logic and just plain bs. To the regulars - I salute you.

For myself and my few audio enthusiast friends, ABX testing on showing whether A is better than B isn't so significant.


Good for you to say that because ABX is not designed for testing preferences.

QUOTE
It is the ABX testing showing there is no difference that is more important. We know that there isn't some next higher level of musical enjoyment that we are missing out on because we haven't invested mega bucks into cables, conditioning sprays or whatever else someone might want to sell. Clarity to cut through the BS and focus on the simple stuff that matters.


When we invented ABX we knew that it was not a tool for testing preferences, so we were a bit worried about how to handle the age-old question of which sounds better. We were frankly stunned when we found that it was often very hard to hear differences among very different components when deprived of sighted and other cues.
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StephenPG
post Dec 2 2012, 16:35
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Recording - room/loudspeaker and nothing else...

It really is that simple.

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