ISO 3951-3:2007 変数による検査のサンプリング手順—パート3：ロットごとの検査のための受入品質限界（AQL）によって索引付けされた二重サンプリングスキーム | ページ 6

3.1

inspection by variables

inspection by measuring the magnitude(s) of the characteristic(s) of an item

[SOURCE: ISO 3534-2:2006, definition 4.1.4]

3.2

sampling inspection

inspection of selected items in the group under consideration

[SOURCE: ISO 3534-2:2006, definition 4.1.6]

3.3

acceptance sampling inspection

acceptance inspection where the acceptability is determined by means of sampling inspection

[SOURCE: ISO 3534-2:2006, definition 4.1.8]

3.4

double sampling inspection, double sampling

acceptance sampling inspection based initially on a first sample, of size n₁, which leads to a decision to accept, non-accept, or to inspect a second sample, of size n₂, before taking the decision whether or not to accept

Note 1 to entry: The decisions are made according to defined rules.

Note 2 to entry: In this part of ISO 3951, both sample sizes are equal and denoted by n, i.e. n₁ = n₂ = n .

3.5

acceptance sampling inspection by variables

acceptance sampling inspection in which the acceptability of the process is determined statistically from measurements on specified quality characteristics of each item in a sample from a lot

[SOURCE: ISO 3534-2:2006, definition 4.2.11]

Note 1 to entry: An acceptable process is a process that generates nonconforming items at a rate no worse than the AQL.

3.6

process average

rate at which nonconforming items are generated by a process

3.7

acceptance quality limit

AQL

worst tolerable product quality level

3.8

quality level

quality expressed as a rate of nonconforming units

3.9

limiting quality

LQ

quality level, when a lot is considered in isolation, which, for the purposes of acceptance sampling inspection, is limited to a low probability of acceptance (in this part of ISO 3951: 10 %)

3.10

nonconformity

non-fulfilment of a requirement

[SOURCE: ISO 9000:2005, definition 3.6.2]

Note 2 to entry: The main text of this part of ISO 3951 deals with the univariate case, for which there will be either one or two classes of nonconformity.

3.11

nonconforming unit

unit with one or more nonconformities

[SOURCE: ISO 3534-2:2006, definition 1.2.15]

3.12

“ s ” method acceptance sampling plan

acceptance sampling plan by variables using the sample mean(s) and sample standard deviation(s)

3.13

“σ” method acceptance sampling plan

acceptance sampling plan by variables using the sample mean(s) and the presumed value(s) of the process standard deviation(s)

3.14

specification limit

limiting value stated for a characteristic

[SOURCE: ISO 3534-2:2006, definition 3.1.3]

3.15

lower specification limit

L

specification limit that defines the lower limiting value

[SOURCE: ISO 3534-2:2006, definition 3.1.5]

3.16

upper specification limit

U

specification limit that defines the upper limiting value

[SOURCE: ISO 3534-2:2006, definition 3.1.4]

3.17

combined control

requirement when nonconformity beyond both the upper and the lower specification limits of a quality characteristic belongs to the same class to which a single AQL is applied

Note 1 to entry: The use of a combined AQL requirement implies that nonconformities beyond either specification limit are believed to be of equal, or at least roughly equal, importance to the lack of integrity of the product.

3.18

separate control

requirement when nonconformity beyond the upper and the lower specification limits of a quality characteristic belongs to different classes, to which separate AQLs are applied

3.19

complex control

requirement when nonconformity beyond both the upper and the lower specification limits of a quality characteristic belongs to one class and nonconformity beyond either the upper or the lower specification limit belongs to a different class, with separate AQLs being applied to the two classes

3.20

acceptability constants

k , p*

constants depending on the specified value of the acceptance quality limit, sample size and inspection severity, used in the criteria for accepting the lot in an acceptance sampling plan by variables

Note 1 to entry: For double sampling, there will be three such pairs of acceptability constants, one for acceptance at the first sample, one for non-acceptance at the first sample and one for acceptance with the combined first and second samples.

3.21

quality statistic

Q

function of the specification limit, the sample mean, and the sample or process standard deviation, used in assessing the acceptability of a lot

[SOURCE: ISO 3534-2:2006, definition 4.4.9]

3.22

lower quality statistic

Q_L

function of the lower specification limit, the sample mean, and the sample or process standard deviation

Note 1 to entry: See Clause 4 for further details.

3.23

upper quality statistic

Q_U

function of the upper specification limit, the sample mean, and the sample or process standard deviation

Note 1 to entry: See Clause 4 for further details.

3.24

maximum sample standard deviation

s_max

MSSD

largest sample standard deviation for a given sample size code letter and acceptance quality limit for which it is possible to satisfy an acceptance criterion for double specification limits when the process variability is unknown

Note 1 to entry: The MSSD depends on whether the double specification limits are under combined, separate or complex control and on the inspection severity (i.e. normal, tightened or reduced).

Note 2 to entry: For double sampling plans, there are two MSSDs under each combination of inspection severity and type of control, one for the first sample and one for the combined first and second samples.

3.25

maximum process standard deviation

σ_max

MPSD

largest process standard deviation for a given sample size code letter and acceptance quality limit for which it is possible to satisfy an acceptance criterion for double specification limits under all inspection severities (i.e. normal, tightened or reduced) when the process variability is known

Note 1 to entry: An MPSD depends on whether the double specification limits are under combined, separate or complex control, but does not depend on the inspection severity or on whether the sample is the first or second.

3.26

switching rule

instruction within an acceptance sampling scheme for changing from one acceptance sampling plan to another of greater or lesser severity based on demonstrated quality history

Note 1 to entry: Normal, tightened or reduced inspection, or discontinuation of inspection, are examples of severity of sampling.

[SOURCE: ISO 3534-2:2006, definition 4.3.4]

3.27

measurement

set of operations having the object of determining the value of a quantity

[SOURCE: ISO 3534-2:2006, definition 3.2.1]

3.28

average sample size

ASSI

average number of units in a sample inspected per lot in reaching decisions to accept or not to accept when using a given acceptance sampling scheme

Note 1 to entry: ASSI is dependent on the actual quality level of the submitted lots.

[SOURCE: ISO 3534-2:2006, definition 4.7.3]

3.29

responsible authority

concept used to maintain the neutrality of this part of ISO 3951, irrespective of whether it is being invoked or applied by the first, second or third party

Note 2 to entry: The duties and functions of a responsible authority are outlined in this part of ISO 3951 (see 5.3, 6, 10, 11, 16.4.3.2.1, 17.1, 19.1, 20.2, 21.4, 23.1, 23.2 and 23.3).