# Commission Regulation (EU) No 801/2010 of 13 September 2010 implementing Article 10(3) of Directive 2009/16/EC of the European Parliament and of the Council as regards the flag State criteria (Text with EEA relevance), Division 1: Flag State performance shall be calculated using a standard formula for statistical calculations in which certain values are fixed. The black to grey and grey to white limits are defined by the following formulas:

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

μ black_to_grey = N · p + 0,5 + z N · p 1 – p μ white_to_grey = N · p – 0,5 – z N · p 1 – p Where:
N is the number of inspections
p is the allowable detention limit
z is the critical value of the normal distribution (1,645 for certainty level of 95 %)

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Source: https://www.legislation.gov.uk/eur/2010/801/annex/division/Flag/division/1 (the official version)
Page: https://openlegislation.uk/eu-regulation-2010-801/annex/division-Flag/division-1
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.