GB/T 6378.4-2018Samling procedures for inspection by variables—Part 4: Procedures for assessment of declared quality levels for mean (English PDF)

Foreword

GB/T 2828 "Counting Sampling Inspection Procedure", GB/T 6378 "Measuring Sampling Inspection Procedure", GB/T 16306 "claiming quality level The assessment procedure for inspection and re-inspection is in common with GB/T 28863, "Sampling inspection procedures for commodity quality supervision with prior quality information" Form the basic series of national standards supporting the sampling inspection work.

GB/T 6378 "Measurement Sampling Inspection Procedures" has been or is planned to release the following parts.

--- Part 1. One-sample side of batch-to-batch inspection of single quality characteristics and single AQL, retrieved by acceptance quality limit (AQL) The provisions of the case;

--- Part 2. General sampling of a single sampling plan for independent quality characteristics retrieved by the acceptance quality limit (AQL) Provision

--- Part 3. Sub-sample plan for batch-by-batch inspections by Retrieval of Acceptance Quality (AQL);

--- Part 4. Assessment procedures for the claimed quality level of the mean;

--- Part 5. Sequential sampling plan for the measurement test retrieved by the acceptance quality limit (AQL);

--- Part 6. Procedure for assessing the quality level of claims for nonconforming product rates.

This part is the fourth part of GB/T 6378.

This part is drafted in accordance with the rules given in GB/T 1.1-2009.

This part replaces GB/T 6378.4-2008 "Measurement sampling test procedures - Part 4: Assessment of the mean quality level of the mean Preface, the main technical changes compared with GB/T 6378.4-2008 are as follows.

--- Increase the sampling plan corresponding to the sample size n=1, and delete the sampling plan corresponding to the sample size n=16 (see Table 1 and Table 2);

--- Change the sampling plan with the test level III to [6, -0.832] to [6, -0.823] (see Table 3, Table 3 of the 2008 edition);

--- Increased the sampling plan corresponding to the sample size n=15, and deleted the sampling plan corresponding to the sample size n=22 (see Table 3);

--- Updated all sampling plans in Table 4 (the design principle changed from approximately normal distribution to t distribution) (see Table 4, 2008 edition) Table 4).

Introduction

The sampling plan and assessment procedures specified in this part of GB/T 6378 are used to assess the quality level of a population (batch or process, etc.).

Whether it does not meet a certain quality level. The sampling plan given in this section minimizes the risk of negating a qualified population (batch).

5%. The sampling plan provided in this section can be used for (but not limited to) testing various products such as final products, parts and raw materials, Operations, work in progress, inventory, maintenance operations, data and records, management procedures, etc.

The scope of this section is different from the first part to the third part of GB/T 6378. Part 1 to Part 3 of GB/T 6378 The system of specified acceptance sampling procedures applies to bilateral agreements between two parties, such as suppliers and consumers. Acceptance sampling procedure only It is used as a rule for judging whether or not to receive a batch of products after testing the samples submitted for inspection. Therefore, these procedures do not explicitly address any form of claim Quality level.

In the acceptance sampling, there is no clear boundary between the acceptable quality of the acceptable batch and the unacceptable batch. For GB/T 6378 The procedures in Parts 1 through 3, the agreed acceptance quality limit is the worst tolerable when submitting a series of consecutive batches. The average quality level of the process.

The transfer rules and sampling plans in GB/T 6378.1 are designed to encourage producers to produce products that have a better AQL good process average quality level. The procedures in Parts 1 and 3 of GB/T 6378 apply to acceptance sampling, but not applicable.

Verify the quality of a verification overall in the review and review. The main reason is that Part 1 and Part 3 of GB/T 6378 are Searching with the acceptance quality limit is only relevant to the actual purpose of the acceptance sample and is therefore balanced for both types of risk.

The sampling inspection procedures specified in this section are designed to be used for the sampling tests required in the formal review. When implementing this form In the case of a type of inspection, the responsible department needs to consider the risk of making a wrong conclusion and consider this in the arrangement and execution review (or review) risk.

This section has some rules designed so that when the actual quality level of the verification overall is in line with the claimed quality level, the overall verification is judged.

The risk of failure is small. If it is also hoped that when the actual quality level of the verification overall does not meet the claimed quality level, the wind passed the verification The risks are also small and require a larger sample size. In order to minimize the sample size, it is allowed when the actual quality level does not actually meet the claimed quality water. Usually, the risk of passing the verification is slightly higher.

The terminology used to determine the outcome reflects an imbalance in the risk of making different erroneous conclusions. When the overall result is unqualified by the sampling result, there is A great grasp is that "the actual quality level of the verification is inferior to the claimed quality level". When the verification result is passed by the sampling result, ". For this limited sample size, the actual quality level of the verification population was not found to be inferior to the claimed quality level". Therefore, when the sample size is small At the time of the verification, the responsible department shall not be responsible for confirming the overall qualification of the verification.

1 Scope

This part of GB/T 6378 specifies a sampling for the measurement of the average of a certain quality characteristic of the overall quality as a quality indicator. Inspection procedure.

The procedures in this section are only applicable to various forms of quality verification, that is, using the test results of the sample to indicate whether a verification is not In the case of meeting a claimed quality level, and the quality characteristics of the product under inspection are subject to or approximate a normal distribution. This section does not apply to batch acceptance sampling.

2 Normative references

The following documents are indispensable for the application of this document. For dated references, only dated versions apply to this document. For undated references, the latest edition (including all amendments) applies to this document.

GB/T 3358.1-2009 Statistical vocabulary and symbols Part 1: General statistical terms and terms used for probability

GB/T 3358.2-2009 Statistical vocabulary and symbols - Part 2: Application statistics

GB/T 6378.1 Measurement sampling procedures - Part 1: Qualitative single quality characteristics and singles retrieved by the acceptance quality limit (AQL) One sampling plan for batch-by-batch inspection of AQL

GB/T 10111 Generation of Random Numbers and Its Application in Product Quality Sampling Inspection

GB/T 16306 claiming procedures for quality level re-examination and re-inspection

3 Terms and definitions

The following terms and definitions as defined in GB/T 3358.1-2009, GB/T 3358.2-2009 and GB/T 6378.1 apply to this file.