# Regulation (EC) No 1222/2009 of the European Parliament and of the Council of 25 November 2009 on the labelling of tyres with respect to fuel efficiency and other essential parameters (Text with EEA relevance), Division 4.2.8.2: Validation of results

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

The μ peak coefficient of variation is calculated as follows:
(Standard Deviation / Average) x 100
For the reference tyre (R) If the coefficient of variation of the peak braking force coefficient ( μ peak ) of the reference tyre is higher than 5 %, all data should be discarded and the test repeated for all test tyres (the candidate tyre(s) and the reference tyre).
For the candidate tyre(s) (T) The coefficient of variation of the peak braking force coefficient ( μ peak ) is calculated for each candidate tyre. If one coefficient of variation is higher than 5 %, the data should be discarded and the test repeated for this candidate tyre.

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Source: https://www.legislation.gov.uk/eur/2009/1222/annex/V/division/4/division/4.2/division/4.2.8/division/4.2.8.2 (the official version)
Page: https://openlegislation.uk/eu-regulation-2009-1222/annex-V/division-4/division-4.2/division-4.2.8/division-4.2.8.2
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.