Division 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: - Directive 2013/53/EU of the European Parliament and of the Council of 20 November 2013 on recreational craft and personal watercraft and repealing Directive 94/25/EC (Text with EEA relevance)

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

x

the individual results obtained from the sample

L

the appropriate limit value

n

the number of engines in the sample

k

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

Division 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: