This standard specifies commonly used statistical quality control terms. This standard applies to statistical quality control terms involved in various standards and technical documents. It should also be used as a reference for quality control terms involved in various research reports and works. GB/T 3358.2-1993 Statistical Terminology Part 2: Statistical Quality Control Terminology GB/T3358.2-1993 Standard download decompression password: www.bzxz.net
This standard specifies commonly used statistical quality control terms. This standard applies to statistical quality control terms involved in various standards and technical documents. It should also be used as a reference for quality control terms involved in various research reports and works.

National Standard of the People's Republic of China
Statistical Terms
Part 2 Terms for Statistical Quality Control
Terms for statistics
-Part F :Terms for statistical quality control Subject Content and Scope of Application
This standard specifies the commonly used statistical quality control terms. GB/T 3358.293
Replaces GB3358
This standard applies to the statistical quality control terms involved in various standards and technical documents. The quality control terms involved in various research reports and works should also be used as a reference.
2 Referenced Standards
GB/T3358.1 Statistical Terms Part 1 General Statistical Terms 3
General Terms
3.1 Process
The implementation procedure of production or service at a specific stage. Example: A process consisting of a certain processing equipment, processing method, materials and a certain (or some) operator. 3.2 Quality quality
The sum of characteristics and properties of a product or process related to its ability to meet specified or potential requirements. 3.3 Quality level qualitylevel
Measure of the relative quality of a product or service compared with relevant requirements. Example: the rate of defective products in a batch and the acceptable quality level. 3.4 Quality measure quality measure
Quantitative expression of quality.
3.5 Quality assurance quality assurance (QA) All planned and systematic activities necessary to ensure that the quality of a product or process meets specified requirements. 3.6 Quality control quality control (QC) The operating techniques and activities taken to meet specified quality requirements. 3.7 Process (quality) control process【quality】 control (PQC) Quality control that keeps the quality of a product or process within the required limits. 3.8 Statistical quality control (SQC) Quality control using statistical techniques.
Acceptance criterion acceptance critcria
The specification requirements for the quality characteristics of a unit product. 3.10 Grade
Approved by the State Administration of Technical Supervision on August 28, 1993, 60
Implemented on May 1, 1994
GB/T 3358.2-93
The classification and grading of products or processes with the same functions according to their quality 3.11 Inspection
The activity of measuring, checking and testing one or more characteristics and comparing them with the specified requirements to determine whether the product or process is qualified.
Process Inspection
The inspection of the characteristics of the process or the product at the appropriate stage of the process. 3.13
Acceptance Inspection The inspection conducted to determine whether the submitted product, batch or service is acceptable. 1 Lot-by-lot inspection 3.14
Each batch in the series of batches is inspected. 5100% inspection100% inspection
Inspection of each product or service within a specific scope. Synonyms: complete inspectionscreening inspection3.161
100% inspection of relevant products or materials to eliminate defective products or unqualified parts. 3.17
rectifying inspectionInspection of all products (or a specified amount of products) in a batch rejected by acceptance sampling to eliminate or replace defective products. 3.18indirect inspectionindirect inspection does not sample the submitted batch, but makes an acceptance inspection to determine whether the batch is acceptable by verifying the supplier's inspection system and inspection results.
3.19 lot, batch
A certain number of products or services collected according to certain conditions. pilot lot
a small batch made by the normal manufacturing process before regular production in order to obtain information and experience, production lot
a quantitative product or a quantitative service produced by a manufacturer under the same conditions within a certain period of time. 3.22 continuing series of lots a series of lots produced continuously by the same manufacturer under the same conditions. 3.23
isolated lot
a lot that is separated from the series of lots that have been produced or collected and does not belong to the current inspection lot series. 3.24
isolated sequence of lots a group of ordered lots that do not form part of a larger series of lots. 3.25 unique lot
a lot made under unique conditions that does not belong to the regular production series. 3.26 inspection lot
a lot submitted for inspection or acceptance.
3.27 consignment
A batch of products delivered at the same time as specified in a set of documents. 3.28
Lot size
The number of unit products in a batch.
Order
A fixed number of products or services ordered from the same manufacturer at the same time. 3.30 sub-group
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A group of products (observations) obtained by grouping a large number of products (observations). 3.31 rational sub-group A large number of products (observations) in an ordered series are divided into some sub-groups. The variation within the group can be considered to be caused by random reasons only. There may be variation between groups caused by abnormal reasons that need to be found. Each of these sub-groups is called a rational sub-group. 3.32 specificationbzxZ.net
A document that specifies the requirements that a product or process must meet. 3.33 Nominal value normal value
The value of a characteristic specified in the design specification and drawings. 3.34 Tolerance limits toleranceancc limits
The maximum and minimum permissible values ​​of a characteristic. Synonym: tolerance limits
3.35 Tolerance tolerance
The difference between the maximum and minimum permissible values ​​of a characteristic. Synonym: tolerance
Tolerance interval
All values ​​between the tolerance limits, including the tolerance limits themselves Synonym: tolerance interval
3.37 Counting method of attributes records whether each individual in a group of objects under investigation has a certain characteristic or attribute, and calculates the number of individuals with the characteristic: or records the number of times a certain characteristic appears in the group of individuals under investigation or within a certain area or a certain amount. 3.38 Quantitative method method of variables measures and records the characteristics of individuals on a continuous scale. 3.39
test
Determination of a characteristic of a product or process under specified conditions. Synonym: test
3.40 nonconformity
Failure of a characteristic of a product or process to meet specifications. 3.41 nonconforming item, nonconforming unit, a unit of product with one or more nonconformities. 3.42 defect
Failure to meet the requirements of the intended use of a quality characteristic. defective item, defective unit3.43
A product with one or more defects.
4 Sampling and acceptance sampling terminology
4.1 Sampling inspection sampling inspectian Inspection of a product or process using a sample of items taken. proportion of nonconforming items, proportion of nonconforning units4.2
The number of nonconforming products in a batch or sample divided by the total number of unit products in it is called the batch or sample nonconforming rate. Note: 100 times the nonconforming rate is called the nonconforming percentage. Nonconformities per hundrcd icms, nonconformitics per hundred unis4.3
“One hundred times the ratio of the total number of nonconformities contained in a certain number of products to the total number of products. Single sampling inspection4.4
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Decide whether to accept the batch based on the inspection results of the sample taken from the batch for the first time. 4.5 Double sampling inspection samplinginspectionFirstly, sample the -th sample of size is drawn from the batch, and according to the inspection results, either decide to accept or reject the batch, or decide to resample the -th sample of size, and then decide to accept or accept the batch according to the inspection results of all samples. 4.6 Multiple sampling inspection multiplesamplinginsptction Sampling is performed at most k times (3). The sample sizes each time are n,,n respectively. After the -th (1=-1)th sample is drawn, the decision to accept or reject the batch or to draw the next sample is made according to the cumulative results of the samples. The decision to accept or reject the batch must be made after the -th sampling.
4.7 Sequential sampling inspection sequential sampling inspection Each time, one or a group of products are drawn from the batch, and after inspection, the decision to accept or reject the batch or to inspect another one or a group of products is made according to a certain rule.
4.8 Continuous sampling inspection continuous sampling Inspection is a sampling inspection of a continuous flow of products (product flow), including: a. Decide whether to accept or reject based on the results of each product inspection; b. Use 100% inspection or sampling inspection based on the observed product quality. When the quality is good, use one or more different sampling ratios: when the quality is poor, use 100% inspection
4.9 Single-level continuous sampling inspection single-level continuous sampling inspection is a sampling inspection of product flow. Based on the observed product quality, use 100% inspection or sampling inspection with a fixed sampling ratio.
4.10 Multi-level continuous sampling inspection muli-level continuous sampling inspection is a sampling inspection of product flow. Based on the observed product quality, use 100% inspection or sampling inspection with two or more sampling ratios.
Chain sampling inspection chain samplinginspection4.11
Sampling inspection using the cumulative sampling results of the current batch and several previous batches within a specified number of days to make a decision on acceptance or rejection: 4.12 Skip-lot sampling inspection For a series of batches, when the sampling results of a specified number of batches meet the specified criteria, the subsequent batches in the series can be accepted without inspection.
4.13 Verification sampling inspection Vcrification sampling inspection A type of sampling inspection that examines whether the sampling procedure of the manufacturer is consistent with the sampling plan he declared (see 4.20). 4.14 Acceptance
Conclusion that a batch or a certain amount of products or services meet the requirements based on the sample. Rejection non-acceptance, rejection 4.15
Conclusion that a batch or a certain amount of products or services do not meet the requirements based on the sample. Note: When used for delivery by the supplier, it means rejection of the batch under contract conditions. Usually, the treatment of rejected batches is specified. 4.16 Acceptance sampling inspection Acceptance sampling inspection The decision on whether a batch can be accepted is made based on the inspection results of samples drawn from the batch. 4.17 Sampling [inspection] plan A specific plan that specifies the sample size and related acceptance criteria. 4.18 Sampling procedure sampling procedure. Sampling inspection requirements and (or) sampling inspection procedures related to the specific sampling plan used. b. The procedure for selecting, drawing and preparing samples from the batch in a planned manner to understand the characteristics of the batch. 4.19 Switching rules Rules for changing from one sampling plan to another more stringent or more lenient sampling plan within a sampling plan based on the proven quality level history.
4.20 Sampling plan sampling $chem GB/T 3358.2—93
- A combination of a sampling plan and switching rules. 4.21 sampling system sampling system a combination of a sampling plan or sampling plan and the criteria for selecting an appropriate sampling plan or sampling plan. 4.22 original inspection original inspection the first inspection of a lot. 4.23 re-submitted lot a lot that is re-submitted for acceptance inspection after sorting and rework have been taken after rejection. 4.24 acceptance number acceptance number in attribute acceptance sampling, the maximum number of non-conforming or unqualified items allowed in a sample of an accepted lot. 5 rejection number, non-acceptance number 4.25 in attribute acceptance sampling, the minimum number of non-conforming or unqualified items allowed in a sample of a rejected lot. 4.26 acceptance constant acceptance constant in measurement acceptance sampling, a constant used to determine whether a lot is acceptable, determined by the acceptable quality level and the sample size.
4.27 Clearance number a. The number of products that must pass 100% inspection in continuous sampling inspection before taking action to reduce the number of inspections. b. The number of batches that must be accepted in batch-by-batch inspection before taking action to reduce the number of inspections in skip sampling inspection. 4.28 Inspection level. Related to the batch sampling ratio: a predetermined index used to express the relative inspection amount in a sampling plan. 4.29 Normal inspection. An inspection used when the product quality level is considered to be consistent with the specified acceptable quality level. 4.30 Tightened inspection. An inspection that is stricter than normal inspection. When the inspection results of a certain number of batches show that the product quality level is worse than the specified quality level, the normal inspection is switched to this type of inspection.
When a certain number of batches are subjected to tightened inspection and the results show that the product quality level has returned to the specified quality level, the tightened inspection is switched back to normal inspection.
4.31 Reduced inspection. An inspection that is looser than normal inspection. When the inspection results of a certain number of batches show that the product quality level is better than the specified quality level, the normal inspection will be transferred to this type of inspection.
When a certain number of batches are subjected to relaxed inspection and the results show that the product quality has dropped to the specified quality level, the relaxed inspection will be returned to the normal inspection.
4.32 Curtailed inspection is a sampling inspection method that saves inspection workload. When the inspection results of some individuals in the sample are sufficient to make a decision on acceptance or collection, the inspection of the remaining individuals will be stopped.
4.33 Severity of sampling: The strictness of the transfer rules in a sampling plan. 4.34 Operating characteristic curve Lof a sampling inspection plan】Category A: For a given sampling plan, the curve that represents the functional relationship between the probability of batch acceptance and the batch quality level. Category B: For a given sampling plan, the curve that represents the functional relationship between the probability of batch acceptance and the process quality level. (In continuous sampling, for a given sampling plan, a curve that represents the functional relationship between the long-term percentage of products accepted under sampling conditions and the process quality level.
Synonym: OC curve
Oc enrvc
Hat Acceptance probability)
Producer risk PR
User risk CR
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PRP (Producer risk point)
Producer risk quality
CRP (User risk point)
User risk quality
Figure 1 OC curve
4.35 Probability of acceptance probability of accepiancePQL
Batch (process) quality
(Downward direction)
The probability of a batch or process with a given quality level being accepted when a certain sampling plan is used. 4.36 probability of rejection, probability of nan-acceptance the probability of rejection of a batch or process with a given quality level when a certain sampling plan is used. consumer's risk (CR) 4.37
for a given sampling plan, the probability of acceptance when the batch or process quality level (e.g., nonconforming product rate) is a specified unsatisfactory value (e.g., limit quality level).
4.38 consumers risk point (CRP) the point on the sampling characteristic curve corresponding to the specified consumer risk. 4.39
consumers risk quality (CRQ) the quality level corresponding to the specified consumer risk for a given sampling plan. producer's risk (PR) 4.40
for a given sampling plan, the probability of rejection when the batch or process quality level (e.g., nonconforming product rate) is a specified acceptable value (e.g., acceptable quality level).
4.41 producer's risk point (PRP) the point on the operating characicristic curve corresponding to the specified producer's risk 4.42 producer's risk quality (PRQ) the quality level corresponding to the specified producer's risk for a given sampling plan. 4.43 slope of the operating characicristic curve of a sampling inspection plan
the slope of the line connecting the producer's risk point and the user's risk point on the operating characicristic curve of a sampling inspection plan. Synonyms: slope of the OC curve Lof a sampling inspection plan) 4.44
indifference zone
the area of ​​quality levels between the acceptable quality level and the limiting quality level in acceptance sampling. 5Indifference point
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The point on the sampling characteristic curve corresponding to the probability of acceptance and the probability of rejection are both equal to 0.5. Synonym: OC curve control point point of control of the O curve4.46Acceptable quality level (AQL) For a continuous batch series, the lowest quality level of the average process that is considered satisfactory for sampling inspection. 4.47Limiting quality level (LQL), for a continuous batch series, the highest quality level of the average process that is considered unsatisfactory for sampling inspection. 4.48Limiting quality (LQ) For an isolated batch, for sampling inspection, the quality level limited to a certain low probability of acceptance. 4.49Average outgoing quality (AOQ) For: ·Qualified products to be accepted. The expected average quality level of the inspected products after inspection using a certain acceptance sampling plan. Average Outgoing Quality Limit (AOQL) 4.50
For a given acceptance sampling plan and lot disposition specification, the maximum value of the average outgoing quality over all possible ranges of product quality to be accepted.
average sample number (ASN), average sample size
The average number of samples per lot to be inspected when a given sampling plan is used to make an acceptance or rejection decision. 4.52 Average amount of inspection The average number of samples per lot to be inspected for a given sampling plan to make a decision on an average lot quality level. Note: The average inspection is an average value within the scope of the transfer rule and does not include the inspection of all products in the rejected lot. 4.53 Average total inspected (ATI) The number of units of product to be inspected per lot calculated based on the sample size of the accepted lot and the size of the rejected lot. Note: This term applies to procedures requiring 100% inspection of rejected lots. 4.54 Maximum average range (MAR) The maximum sample average range allowed for the acceptance batch when the variable inspection is carried out according to the combined two-sided specification limits. 4.55 Maximum process standard deviation (MPSD) The maximum value of the process standard deviation of the acceptance batch when the variable inspection is carried out according to the combined two-sided specification limits. 4.56 Maximum sample standard deviation (MSSD) The maximum value of the sample standard deviation of the acceptance batch when the variable inspection is carried out according to the combined two-sided specification limits 5 Process measurement terms
5.1 Process levelprocess level
The characteristic value of a specific stage of the process. It determines the quality level of the process. Note: In most cases, the process level is expressed as the rate of defective products or the percentage of defective products. 5.2 Process averageprocess average
-The average value of the process level within a certain period of time or a quantitative product range. 5.3 Within-lot variationwithin-lot variationThe degree of fluctuation of a characteristic of a product within a batch. 5.4Between-lot variationThe degree of fluctuation of the average value of a characteristic of each batch. 5.5State of statistical controlThe state in which the variation between sample test results is caused by a series of random causes and does not change systematically over time. 5.6Process in control, stable processEach quality indicator of the process (such as mean, variation or defective rate, etc.) is in a state of statistical control. 5.7Systematic variations66
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Variation caused by non-random causes in a controlled process. 5.8Assignable causeAssignable factors that cause changes in quality characteristics or process levels. 5.9Chance causes
Some factors that cause changes in quality characteristics or process levels that cannot or are not easy to identify. The number may be large, but the impact of each is quite small.
5.10 Inherent process variability (IPV) The variation of a process when it is in a state of statistical control. Note: When a process is processed by a certain method using a control device (or a production line), a group of operators and a batch of uniform materials, its inherent variability is smaller than when several devices, several groups of operators and several batches of materials are processed by the same processing method. 5.11 Total process variability The sum of the inherent variation of the process and the variation caused by factors that may change (such as operator errors, abnormal adjustment or wear of equipment, non-standard materials or other abnormal reasons). 5.12 Process capability A measure of the inherent variation of the process.
5.13 Natural process limits The limit values ​​of the product characteristics containing specified ratios in the population. 5.14 Process interval, natural process interval The difference between two inherent limits of a process.
Process capability index (PC) The quotient of the tolerance (tolerance) specified by the process capability divided by the process capability 5.16 Control chart control chart
A chart that plots the values ​​of a statistic based on successively drawn samples or subgroups (see 3.30) and draws control limits, used to evaluate and monitor whether a process is under control. Conventional control chart conventional control chart, Shewhart control chart 5.17
A type of control chart that uses count values ​​(such as defective rate) or measurement values ​​(such as mean and range) to evaluate and or monitor a process. 5.18 Average chart average chart
A control chart that uses the mean of a subgroup to evaluate and monitor a process. 5.19 Median chart median chart
A control chart that uses the median of a subgroup to evaluate and monitor a process. 5.20 Individual observations chart, original data chart A control chart that uses the individual observations of a sample to evaluate and monitor a process. Standard deviation chart standard deviation chart5.21
A control chart that uses the standard deviation of a subgroup to evaluate and monitor the process. 5.22
Range chart range chart
A control chart that uses the range of a subgroup to evaluate and monitor the process. Count chart
A control chart that uses the number of certain types of nonconformities in a sample to evaluate and monitor the process. 5.24
Count per unit chart of nonconformities in a sample of a certain type of nonconformities, a control chart that uses the average number of certain types of nonconformities in a sample of a unit product, to evaluate and monitor the process. 5.25 Fraction chart, proportion chart A control chart that uses the rate of certain types of nonconformities in a sample to evaluate and monitor the process. 6 Percent chart of nonconformities percent chart5.26
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A control chart that uses the fraction of certain types of nonconformities in a sample to evaluate and monitor the process. 5.27 Number of nonconforming items chart A control chart that uses the number of nonconforming items of a certain type in a sample to evaluate and monitor a process. 5.28 Quality score chart A control chart that uses a certain defect (or quality score), such as the weighted sum of the number of nonconforming items of each type, to evaluate and monitor a process. Synonym: Demerit chart. 5.29 Universal control chart A control chart obtained by standardizing the statistics used in conventional control charts. 5.30
Cumulative sum chart, cusum chart A control chart that uses the cumulative sum of the differences between the sample statistics and the national standard values ​​to evaluate and monitor a control process. Acceptance control chart5.31
A control chart used to evaluate a process for the following two purposes: a. To predict whether the process can meet the product tolerance (tolerance) for the measured characteristic; b. To evaluate whether the process is in a state of statistical control based on the variation within the group. 5.32 Adaptive control chart Adaptive control chart A control chart. When the process does not need to be changed, it uses the process prediction model to estimate its future development trend; and when the process needs to be changed, it gives the amount of change to control the process bias within an acceptable range. 5.33
3 Moving Average Control Chart Moving Average Control Chart uses the arithmetic mean of the most recent observations to evaluate and monitor the process level control chart. 5.34
Exponentially Weighted Moving Average Control Chart Exponentially Weighted Moving Average Control Chart uses the exponentially smoothed moving average to evaluate and monitor the process level control chart. 5.35 Moving Range Control Chart Moving Range Control Chart uses the range of the most recent observations to evaluate and monitor the variability within the process. 5.36 Trend Control Chart Trend Control Chart uses the expected deviation of the subgroup mean from the process level to evaluate and monitor the process level control chart. 5.37 Multivariate Quality Control Multivariate Quality Control is a quality control in which each product inspected must meet two or more characteristic specifications. 5.38 Multivariate control chart A control chart that uses the changes in the levels of two or more characteristics to evaluate and monitor a process. 5.39 Control limits Control limits
Limits on a control chart used to determine whether a process is in statistical control. Note: Control limits are divided into upper control limits and lower control limits. When a process is in statistical control, the statistic under consideration will be between the upper and lower control limits with a high probability. 5.40 Acceptance control limits Acceptance control limits (ACL) Limits on an acceptance control chart used to decide whether action is needed. 5.41 Action limits Action limits
Limits on a control chart used to decide whether action is needed. Warning limits Warning limits
Limits on a chart used to decide whether a warning signal needs to be issued. 3 Center line (CL)
Line on a control chart representing the long-term average or predetermined value of a statistic. 5.44 Control chart facton A coefficient that converts a specified statistic or parameter into a center line value or control limit appropriate for a control chart as the sample size changes. 68
5.45 Run
GB/T3358.2-93
A sequence of adjacent data points on a control chart that have the same characteristics. 5.46 Runlength
The number of data points contained in a chain.
5.47 Average run length (ARL) a.
The average number of times a process is sampled and evaluated before a change in process level is signaled.
The average number of units manufactured before a change in process level is signaled. b.
Zone of acceptable processes 5.48
A zone of standard or center level that includes the process level that is almost always acceptable. 9Acceptable process level (APL) 5.49
The process level that forms the boundary of the acceptable process area. Zone of rejectable processes 5.50
The area located at or outside the rejectable process level, including the process level that is almost always rejected. 5.51
Rejectable process level (RPL) is the process level that forms the boundary of the rejectable process area. Indifference zone (acceptance control chart usagc) is the area between the acceptable process area and the rejectable process area on the acceptance control chart (i.e., the area between the acceptable process level and the acceptable process level).
Rejectable process city
Indeterminate domain
/////
Acceptable process city
Figure 2 Acceptance control chart
.Target level
A1 Common symbols and corresponding terms (see Table A1) Symbol
GB/T3358.2-93
Appendix A
Common symbols and abbreviations
(Supplement)
Sample size (single sampling inspection)
Sample size (secondary sampling inspection)
Risk of the producer
Risk of the user
Acceptance number||t t||Number of rejections
Probability of acceptance
Abbreviations of commonly used terms (see Table A2)
Term abbreviations
Acceptance control limit
Average inspection quality or
Average inspection quality upper limit
Acceptable process level
Acceptable quality level
Average chain length
Average sample size
Average total number of inspections
Center line
User risk
User risk point
Reference items
Reference items
Term abbreviations
GB/T 3358.2—93
Continued Table A2
User Risk Quality
Lower Control Limit
Limit Quality
Limit Quality Level
Maximum Average Range
Maximum Process Standard Deviation
Maximum Sample Standard Deviation
Process Capability Index
Process Quality Based Control
Producer Risk
Producer Risk Point
Producer Risk Quality
Quality Assurance
Quality Control
Rejectable Process Level
Statistical Quality Control
Upper Control Limit
Reference Item
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