# Commission Regulation (EEC) No 2568/91 of 11 July 1991 on the characteristics of olive oil and olive-residue oil and on the relevant methods of analysis, Division 9.5: Criteria for the acceptance and rejection of duplicates

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

The normalised error, defined below, shall be used to determine whether the two results of a duplicate analysis are homogenous or statistically acceptable:
E n = Me 1 − Me 2 2 U 2 1 + U 2 2
Where Me 1 and Me 2 are the medians of the two duplicates (respectively first and second analysis) and U 1 and U 2 are the expanded uncertainties obtained for the two values, calculated as follows as specified in Appendix:
U 1 = c × s * and s * = CV r × Me 1 100
For the expanded uncertainty, c = 1,96; hence:
U 1 = 0,0196 × CV r × M e1
where CV r is the robust coefficient of variation.
For it to be stated that the two values obtained are not statistically different, E n must be equal to or less than 1,0.

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Source: https://www.legislation.gov.uk/eur/1991/2568/annex/XII/division/9/division/9.5 (the official version)
Page: https://openlegislation.uk/eu-regulation-1991-2568/annex-XII/division-9/division-9.5
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.