[ANNEX II U.K.
2. REQUIREMENTS FOR CHECKING BATCHES OF PREPACKAGES] U.K.
2.3.Checking of the average actual contents of the individual prepackages making up a batchU.K.
2.3.1.A batch of prepackages shall be considered acceptable for the purpose of this check if the mean value of the actual contents xi of n prepackages in a sample is greater than the value:U.K.
In this formula:
Qn
=
the nominal quantity of the prepackage,
n
=
the number of prepackages in the sample for this check,
s
=
the estimated standard deviation of the actual contents of the batch,
t(1 — α)
=
0.995 confidence level of a Student distribution with ν = n — 1 degree of freedom.
2.3.2.If xi is the measured value for the actual contents of the i-th item in the sample containing n items then:U.K.
2.3.2.1.the mean of the measured values for the sample is obtained by the following calculation:U.K.
2.3.2.2.and the estimated value of the standard deviation s by the following calculation:U.K.
the estimated value of the standard deviation is:
2.3.3.Criteria for acceptance or rejection of the batch of prepackages for checking the mean:U.K.
2.3.3.1.Criteria for non-destructive testingU.K.
Number in batch | Number in sample | Criteria |
---|
Acceptance | Rejection |
---|
100 to 500 (inclusive) | 30 | | |
> 500 | 50 | | |
2.3.3.2.Criteria for destructive testingU.K.
Number in batch | Number in sample | Criteria |
---|
Acceptance | Rejection |
---|
Whatever the number (≥100) | 20 | | |