# Commission Regulation (EC) No 152/2009 of 27 January 2009 laying down the methods of sampling and analysis for the official control of feed (Text with EEA relevance), Division 7.3.1

Extent: E+W+S+N.I.

Use of the lower band of the 95 % prediction interval at the decision limit of the confirmatory method:
Cut-off value=BEQDL−sy,x×t α,f=m−21∕n+1∕m+xi−x–2∕Qxx
with:
BEQ DL BEQ corresponding to the decision limit of the confirmatory method, being the maximum level taking into account the expanded measurement uncertainty
s y,x residual standard deviation
t α,f = m – 2 student factor (α = 5 %, f = degrees of freedom, single-sided)
m total number of calibration points (index j)
n number of repetitions on each level
x i sample concentration (in TEQ) of calibration point i determined by a confirmatory method
x–mean of the concentrations (in TEQ) of all calibration samples
Qxx=∑j=1mxi−x–2 square sum parameter, i = index for calibration point i

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Source: https://www.legislation.gov.uk/eur/2009/152/annex/V/division/B/chapter/II/division/7/division/7.3/division/7.3.1 (the official version)
Page: https://openlegislation.uk/eu-regulation-2009-152/annex-V/division-B/chapter-II/division-7/division-7.3/division-7.3.1
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.