#38491 - 08/13/02 05:20 PM
Re: What up...?
|
Desperado
Registered: 04/10/02
Posts: 1857
Loc: Gusev Crater, Mars
|
***Anyone that knows anything about trial design, knows that correctly designed and implemented DBTs are virtually impossible when comparing electronics. An incorrect or flawed DBT may introduce errors which can make the results of the DBT neither reliable nor valid. ***
Really..... see my post above. How hard could doing a single blind comparason without you knowing the identies of the units be? The volume difference issue could be easily solved by having the assistant reducing the volume to zero on each unit as it is put into the system, and you adjust it to taste from there. Personally, I wouldn't take the time to do such a comparason, since, being the outcast that I am, believe that the sound difference in most electronics is swamped by the differences in program material / how your hearing is on a particular day / if you just had an argument with the significant other / relative humidity / sound absorbtion from more people in the room etc.
|
Top
|
|
|
|
|
#38492 - 08/13/02 05:47 PM
Re: What up...?
|
Desperado
Registered: 04/20/01
Posts: 369
Loc: Deep in the Woodlands of Texas
|
How hard could doing a single blind comparason without you knowing the identies of the units be? Soundhound: Single Blind is NOT DBT(Double Blind Testing). And, Single blind testing introduces all its' own inherent biases and errors as a result of the investigator's knowledge of the unit being tested and the lack of testing randomness.
|
Top
|
|
|
|
|
#38493 - 08/13/02 06:09 PM
Re: What up...?
|
Desperado
Registered: 04/10/02
Posts: 1857
Loc: Gusev Crater, Mars
|
***Single Blind is NOT DBT(Double Blind Testing). And, Single blind testing introduces all its' own inherent biases and errors as a result of the investigator's knowledge of the unit being tested and the lack of testing randomness.***
We're not talking about rocket science or creative accounting practices here - simply which do you prefer!!!
|
Top
|
|
|
|
|
#38494 - 08/13/02 06:29 PM
Re: What up...?
|
Gunslinger
Registered: 01/31/02
Posts: 187
Loc: austin, tx
|
Why would single blind inherently lack randomness?
brianca
|
Top
|
|
|
|
|
#38495 - 08/13/02 06:32 PM
Re: What up...?
|
Desperado
Registered: 04/20/01
Posts: 369
Loc: Deep in the Woodlands of Texas
|
Why would single blind inherently lack randomness? Because someone is making an active decision as to which unit is being tested, when, and in what order.
|
Top
|
|
|
|
|
#38496 - 08/13/02 06:33 PM
Re: What up...?
|
Desperado
Registered: 04/10/02
Posts: 1857
Loc: Gusev Crater, Mars
|
Single blind can have as much randomness and double blind, it's just that the order of the 'subjects' is determined by a tester, who knows the identites of the units.
|
Top
|
|
|
|
|
#38497 - 08/13/02 06:35 PM
Re: What up...?
|
Desperado
Registered: 04/10/02
Posts: 1857
Loc: Gusev Crater, Mars
|
In that case, the tester can create a random number generator, using sophisticated scientific methods - like, uh, flipping a coin or something.....
|
Top
|
|
|
|
|
#38498 - 08/13/02 06:47 PM
Re: What up...?
|
Desperado
Registered: 04/20/01
Posts: 369
Loc: Deep in the Woodlands of Texas
|
We're not talking about rocket science or creative accounting practices here - simply which do you prefer!!! EXACTLY my point. I prefer careful crossover listening without all the rocket science. However, if you intend on going the science route, either do it right or you're doing it wrong. In that case, the tester can create a random number generator, using sophisticated scientific methods - like, uh, flipping a coin or something..... Having an investigator come up with and manually select the unit for testing, opens the protocol to suspicion and questioning, and probably introduces testing error variables which can confound the results thereby increasing the total trials needed to reach a significant p value. If your study can reach a significant p value in ten tests or fewer, then the difference is so significant and obvious as to make the blind testing un-necessary in the first place. Why not carefully listen to each unit a few times and then if you cannot discern a difference or make a decision, either buy the cheaper unit or then do your blinded testing?
|
Top
|
|
|
|
|
#38499 - 08/13/02 07:32 PM
Re: What up...?
|
Desperado
Registered: 01/14/02
Posts: 1176
|
Originally posted by merc: However, if you intend on going the science route, either do it right or you're doing it wrong. I couldn't agree more - and no, I'm not in the drug business. [B]Why not carefully listen to each unit a few times and then if you cannot discern a difference or make a decision, either buy the cheaper unit or then do your blinded testing? Um, because you're biased, like it or not? If the differences are signifcant as is often claimed, a double blind test (ABX or not) will show it. Charlie
_________________________
Charlie
|
Top
|
|
|
|
|
#38500 - 08/13/02 07:33 PM
Re: What up...?
|
Desperado
Registered: 04/10/02
Posts: 1857
Loc: Gusev Crater, Mars
|
***Why not carefully listen to each unit a few times and then if you cannot discern a difference or make a decision, either buy the cheaper unit or then do your blinded testing? ***
Well, that was exactly my point in the first place. Going the scientific route is pretty pointless, I think, for something so elemental as home theatre, but you had previously asked me how I would propose to compare a 1066 vs a 950 in a blind situation, and I told you. I did not propose to make the test any more sophisticated than it deserves to be. You are absolutely right in that if you do only a few trials and can hear a difference, then the difference must be so gross that ANY comparasion (dare I say an ABX test...sorry...) would pick it up.
|
Top
|
|
|
|
|
|
0 registered (),
131
Guests and
2
Spiders online. |
Key:
Admin,
Global Mod,
Mod
|
|
|
8,717 Registered Members
88 Forums
11,331 Topics
98,703 Posts
Most users ever online: 677 @ 09/27/24 06:41 PM
|
|
|
|