lol its out of subject , but realy interested.
Its rise the measurement problem.
I think for each apparel its like that .
i saw a video , the guy were testing 4 thermometers ( from 4 different brand ) .
Probe at same place , same height well all same , for 4 different results lol .
and not small difference , the range was between 5 degres ....
like one measure 20° and one other was at 25° .
Hard to make an average if the measure conditions are strictly the same for each apparel right ?
So which value you choose in this case ?
Its same for Ph probe etc....
structure like LHC , Cern got stuff ultra precise and they are sure of the apparel calibration.
the most important , you can have weighing scale precise at 0.00000 gr , if it bad calibrate , the measure will be precise , but false.
i say that , i used 4 ph probe , blue line , hanna ect .. each time got surprised with, in despite the maintenance i've done (clean, storage, etc ... )
But i supposed , its not very serious thing for us , even if , no one could well lead futures in hydro culture for example , where we got to control and have good measure of the environement