Schedule 7 (Annex VII of the Directive)I1

United Kingdom

1.
For verifying the conformity of an engine family, a sample of engines shall be taken from the series. The manufacturer shall decide the size (n) of the sample, in agreement with the ~~F1notified~~ approved body.
2.
The arithmetical mean X of the results obtained from the sample shall be calculated for each regulated component of the exhaust and noise emission. The production of the series shall be deemed to conform to the requirements (‘pass decision’) if the following condition is met:
$X + k. S \leq L$
S is standard deviation, where:
$S^{2} = \sum {(x - X)}^{2} ∕ (n - 1)$ X
the arithmetical mean of the results obtained from the sample
the individual results obtained from the sample
the appropriate limit value
the number of engines in the sample
statistical factor depending on n (see table below)

n	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19
If n ≥ 20 then $k = 0,860 ∕ \sqrt{n}$ .
k	0,973	0,613	0,489	0,421	0,376	0,342	0,317	0,296	0,279	0,265	0,253	0,242	0,233	0,224	0,216	0,21	0,203	0,198

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