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Another example of NONscience (edge retention comparison)

Posted by CliffStamp 
Another example of NONscience (edge retention comparison)
August 02, 2020 08:59AM
Video :

[www.youtube.com]

-the conclusion is that the blade became sharper

The data doesn't support that at all. For 20+ years, myself (and others) have been talking about the need for BASIC procedures in comparisons, how is this still not well understood, this is first year science :

-all measurements have error (uncertainty)
-if you don't have an uncertainty you don't even have a measurement

The knife is measured for sharpness one time in :

-two different places
-two different pieces of cord
-two different clips

and since they are not exactly the same number, concludes the knife is "sharper" .

-knives do not have the same sharpness along the edge
-all cord varies (even ISO grades)
-all measurements have uncertainties (even NSERC labs)

Minimal procedure :

-make 3-5 measure of sharpness
-calculate an average and standard deviation

Then when you compare, see if the standard deviations over lap, if they do, then the numbers are not different.

(there are better ways, but this is the most BASIC)



Edited 1 time(s). Last edit at 08/02/2020 09:06AM by CliffStamp.
Re: Another example of NONscience (edge retention comparison)
August 02, 2020 11:10AM
Quote
CliffStamp
Minimal procedure :

-make 3-5 measure of sharpness
-calculate an average and standard deviation

Then when you compare, see if the standard deviations over lap, if they do, then the numbers are not different.

(there are better ways, but this is the most BASIC)

That’s almost exactly the standard procedure for measuring bullet speed over a chronograph.

For a basic rough measurement you make 3 to 5 shots and get the average, standard deviation, and extreme spread. If you really wanna know, you make 20 or more shots, the whole box of ammo, and then get your average, SD, and ES. Nobody in their right mind, even in the gun world which is absolutely full to the brim with nonsensical crap, would ever make a single shot over a chronograph and say it was a meaningful measurement.
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