Division 5.10.5 Pass/Fail decision for a sampleF1

For the purposes of deciding on a pass/fail result for the sample, ‘p’ is the count of passed results, and ‘f’ is the count of failed results. Each passed test result shall increase the ‘p’ count by 1 and each failed test result shall increase the ‘f’ count by 1 for the relevant open statistical procedure.

Upon the incorporation of valid emission test results to an open instance of the statistical procedure, the type approval authority shall perform the following actions:

• update the cumulative sample size ‘n’ for that instance to reflect the total number of valid emissions tests incorporated to the statistical procedure;

• following an evaluation of the results, update the count of passed results ‘p’ and the count of failed results ‘f’;

• compute the number of extreme and intermediate outliers in the sample in accordance with point 5.10.4.

• check whether a decision is reached with the procedure described below.

The decision depends on the cumulative sample size ‘n’, the passed and failed result counts ‘p’ and ‘f’, as well as the number of intermediate and/or extreme outliers in the sample. For the decision on a pass/fail of an ISC sample the granting type approval authority shall use the decision chart in Figure B.2 for vehicles based on types approved as of1 January 2020 and the decision chart in Figure B.2.a for vehicles based on types approved until 31 December 2019. The charts indicate the decision to be taken for a given cumulative sample size ‘n’ and failed count result ‘f’.

Two decisions are possible for a statistical procedure for a given combination of vehicle family, emissions test type and pollutant:

‘Sample pass’ outcome shall be reached when the applicable decision chart from Figure B.2 or Figure B.2.a gives a ‘PASS’ outcome for the current cumulative sample size ‘n’ and the count of failed results ‘f’.

‘Sample fail’ decision shall be reached when, for a given cumulative sample size ‘n’, when at least one of the following conditions is fulfilled:

• the applicable decision chart from Figure B.2 or Figure B.2.a gives a ‘FAIL’ decision for the current cumulative sample size ‘n’ and the count of failed results ‘f’.

• there are two intermediate outliers;

• there is one extreme outlier.

If no decision is reached, the statistical procedure shall remain open and further results shall be incorporated into it until a decision is reached or the procedure is closed in accordance with point 5.10.1.