http://www.legislation.gov.uk/id/eudr/1976/211/annex/II/division/2

F1ANNEX II

Annotations:

Amendments (Textual)

A batch of prepackages shall be considered acceptable for the purpose of this check if the mean value

x^{-} = \frac{\sum x_{i}}{n}

of the actual contents x_i of n prepackages in a sample is greater than the value:

Q_{n} - \frac{s}{\sqrt{n}} \times t_{(1 - α)}

In this formula:

Q_n: 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.

If x_i is the measured value for the actual contents of the i-th item in the sample containing n items then:

the mean of the measured values for the sample is obtained by the following calculation:

x^{-} = \frac{\sum_{i = 1}^{i = n} x_{i}}{n}

and the estimated value of the standard deviation s by the following calculation:

the sum of the squares of the measured values: $\sum_{i = 1}^{i = n} {(x_{i})}^{2}$
the square of the sum of the measured values: ${(\sum_{i = 1}^{i = n} x_{i})}^{2}$
then $\frac{1}{n} {(\sum_{i = 1}^{i = n} x_{i})}^{2}$
the corrected sum $SC = \sum_{i = 1}^{i = n} \frac{SC = \sum^{i = n} {(x_{i})}^{2} - 1}{n} {(\sum_{i = 1}^{i = n} x_{i})}^{2}$
the estimated variance: $v = \frac{SC}{n — 1}$

the estimated value of the standard deviation is:

s = \sqrt{v}

Criteria for acceptance or rejection of the batch of prepackages for checking the mean:

Criteria for non-destructive testing

Criteria for destructive testing

Number in batch	Number in sample	Criteria
Number in batch	Number in sample	Acceptance	Rejection
Whatever the number (≥100)	20	$x^{-} \geq Q_{n} — 0.640s$	$x^{-} < Q_{n} — 0.640s$