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Acceptance Sampling
Acceptance sampling uses statistical sampling to determine whether to accept or reject a production lot of material. It has been a common quality control technique used in industry. It is usually done as products leave the factory, or in some cases even within the factory. Most often a producer supplies a consumer with several items and a decision to accept or reject the items is made by determining the number of defective items in a sample from the lot. The lot is accepted if the number of defects falls below where the acceptance number or otherwise the lot is rejected. In general, acceptance sampling is employed when one or several of the following hold: * testing is destructive; * the cost of 100% inspection is very high; and * 100% inspection takes too long. A wide variety of acceptance sampling plans is available. For example, multiple sampling plans use more than two samples to reach a conclusion. A shorter examination period and smaller sample sizes are features of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Statistical Sampling
In this statistics, quality assurance, and survey methodology, sampling is the selection of a subset or a statistical sample (termed sample for short) of individuals from within a statistical population to estimate characteristics of the whole population. The subset is meant to reflect the whole population, and statisticians attempt to collect samples that are representative of the population. Sampling has lower costs and faster data collection compared to recording data from the entire population (in many cases, collecting the whole population is impossible, like getting sizes of all stars in the universe), and thus, it can provide insights in cases where it is infeasible to measure an entire population. Each observation measures one or more properties (such as weight, location, colour or mass) of independent objects or individuals. In survey sampling, weights can be applied to the data to adjust for the sample design, particularly in stratified sampling. Results from probab ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Verifying
Verification and validation (also abbreviated as V&V) are independent procedures that are used together for checking that a product, service, or system meets requirements and specifications and that it fulfills its intended purpose. These are critical components of a quality management system such as ISO 9000. The words "verification" and "validation" are sometimes preceded with "independent", indicating that the verification and validation is to be performed by a disinterested third party. "Independent verification and validation" can be abbreviated as "IV&V". In reality, as quality management terms, the definitions of verification and validation can be inconsistent. Sometimes they are even used interchangeably. However, the PMBOK guide, a standard adopted by the Institute of Electrical and Electronics Engineers (IEEE), defines them as follows in its 4th edition: * "Validation. The assurance that a product, service, or system meets the needs of the customer and other ident ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ASTM International
ASTM International, formerly known as American Society for Testing and Materials, is a standards organization that develops and publishes voluntary consensus technical international standards for a wide range of materials, products, systems and services. Some 12,575 apply globally. The headquarters is in West Conshohocken, Pennsylvania, about northwest of Philadelphia. It was founded in 1902 as the American Section of the International Association for Testing Materials. In addition to its traditional standards work, ASTM operates several global initiatives advancing additive manufacturing, advanced manufacturing, and emerging technologies, including the Additive Manufacturing Center of Excellence (AM CoE), the acquisition oWohlers Associatesfor market intelligence and advisory services, and the National Institute of Standards and Technology, NIST-funded Standardization Center of Excellence (SCOE). History In 1898, a group of scientists and engineers, led by chemist, industry ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Variables Sampling Plan
In statistics, a variables sampling plan is an acceptance sampling technique. Plans for variables are intended for quality characteristics that are measured on a continuous scale. This plan requires the knowledge of the statistical model (e.g. normal distribution). The historical evolution of this technique dates back to the seminal work of W. Allen Wallis (1943). The purpose of a plan for variables is to assess whether the process is operating far enough from the specification limit. Plans for variables may produce a similar OC curve to attribute plans with significantly less sample size. The decision criterion of these plans are : \bar+ k\sigma \leqslant USL or \bar- k\sigma \geqslant LSL where \bar and \sigma are the sample mean and the standard deviation respectively, k is the critical distance, USL and LSL are the upper and lower regulatory limits. When the above expression is satisfied the proportion nonconforming is lower than expected and therefore the lot is accepted ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acceptance Testing
In engineering and its various subdisciplines, acceptance testing is a test conducted to determine if the requirements of a specification or contract are met. It may involve chemical tests, physical tests, or performance tests. In systems engineering, it may involve black-box testing performed on a system (for example: a piece of software, lots of manufactured mechanical parts, or batches of chemical products) prior to its delivery. In software testing, the ISTQB defines ''acceptance testing'' as: The final test in the QA lifecycle, user acceptance testing, is conducted just before the final release to assess whether the product or application can handle real-world scenarios. By replicating user behavior, it checks if the system satisfies business requirements and rejects changes if certain criteria are not met. Some forms of acceptance testing are, user acceptance testing (UAT), end-user testing, operational acceptance testing (OAT), acceptance test-driven developm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acceptability
Acceptability is the characteristic of a thing being subject to acceptance for some purpose. A thing is acceptable if it is sufficient to serve the purpose for which it is provided, even if it is far less usable for this purpose than the ideal example. A thing is unacceptable (or has the characteristic of unacceptability) if it deviates so far from the ideal that it is no longer sufficient to serve the desired purpose, or if it goes against that purpose. Acceptability is an amorphous concept, being both highly subjective and circumstantial; a thing may be acceptable to one evaluator and unacceptable to another, or unacceptable for one purpose but acceptable for another. Furthermore, acceptability is not necessarily a logical or consistent exercise. A thing may be sufficient to serve a particular purpose but in the subjective view of the decision maker be unacceptable for that purpose. Dov M. Gabbay, Odinaldo T. Rodrigues, Alessandra Russo, ''Revision, Acceptability and Context: The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sample Size
Sample size determination or estimation is the act of choosing the number of observations or replicates to include in a statistical sample. The sample size is an important feature of any empirical study in which the goal is to make inferences about a population from a sample. In practice, the sample size used in a study is usually determined based on the cost, time, or convenience of collecting the data, and the need for it to offer sufficient statistical power. In complex studies, different sample sizes may be allocated, such as in stratified surveys or experimental designs with multiple treatment groups. In a census, data is sought for an entire population, hence the intended sample size is equal to the population. In experimental design, where a study may be divided into different treatment groups, there may be different sample sizes for each group. Sample sizes may be chosen in several ways: *using experience – small samples, though sometimes unavoidable, can result in wid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Operating Characteristic Curve
Operation or Operations may refer to: Arts, entertainment and media * ''Operation'' (game), a battery-operated board game that challenges dexterity * Operation (music), a term used in musical set theory * ''Operations'' (magazine), Multi-Man Publishing's house organ for articles and discussion about its wargaming products * ''The Operation'' (film), a 1973 British television film * ''The Operation'' (1990), a crime, drama, TV movie starring Joe Penny, Lisa Hartman, and Jason Beghe * The Operation M.D., formerly The Operation, a Canadian garage rock band * "Operation", a song by Relient K from '' The Creepy EP'', 2001 Television Episodes * "The Operation", ''Sky Dancers'' episode 27 (1996) * "The Operation", ''The Golden Girls'' season 1, episode 18 (1986) * "The Operation", ''You're Only Young Twice'' (1997) series 2, episode 8 (1978) Shows * ''The Operation'' (1992–1998), a reality television series from TLC Business * Manufacturing operations, operation of a f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acceptable Quality Limit
The acceptable quality limit (AQL) is the worst tolerable process ''average'' (''mean'') in percentage or ratio that is still considered acceptable; that is, it is at an acceptable quality level.Dodge, Y. (2003) ''The Oxford Dictionary of Statistical Terms''. OUP. Closely related terms are the rejectable quality limit and rejectable quality level (RQL). In a quality control procedure, a process is said to be at an acceptable quality level if the appropriate statistic used to construct a control chart does not fall outside the bounds of the acceptable quality limits. Otherwise, the process is said to be at a rejectable control level. In 2008 the usage of the abbreviation AQL for the term "acceptable quality limit" was changed in the standards issued by at least one national standards organization (ANSI/ ASQ) to relate to the term "acceptance quality level".http://www.aqlinspectorsrule.com/Z1-4-2008.html ''AQL Inspectors Rule'' It is unclear whether this interpretation will be b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Technical Specifications
A specification often refers to a set of documented requirements to be satisfied by a material, design, product, or service. A specification is often a type of technical standard. There are different types of technical or engineering specifications (specs), and the term is used differently in different technical contexts. They often refer to particular documents, and/or particular information within them. The word ''specification'' is broadly defined as "to state explicitly or in detail" or "to be specific". A requirement specification is a documented requirement, or set of documented requirements, to be satisfied by a given material, design, product, service, etc. It is a common early part of engineering design and product development processes in many fields. A functional specification is a kind of requirement specification, and may show functional block diagrams. A design or product specification describes the features of the ''solutions'' for the Requirement Specification ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ISO 9000
The ISO 9000 family is a set of international standards for Quality (business), quality management systems. It was developed in March 1987 by International Organization for Standardization. The goal of these standards is to help organizations ensure that they meet customer and other Stakeholder (corporate), stakeholder needs within the statutory and regulatory requirements related to a product or service. The standards were designed to fit into an integrated management system. The ISO refers to the set of standards as a "family", bringing together the standard for quality management systems and a set of "supporting standards", and their presentation as a family facilitates their integrated application within an organisation. ISO 9000 deals with the fundamentals and vocabulary of QMS, including the seven quality management principles that underlie the family of standards. ISO 9001 deals with the requirements that organizations wishing to meet the standard must fulfill. A companion ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quality Control
Quality control (QC) is a process by which entities review the quality of all factors involved in production. ISO 9000 defines quality control as "a part of quality management focused on fulfilling quality requirements". This approach places emphasis on three aspects (enshrined in standards such as ISO 9001): # Elements such as controls, job management, defined and well managed processes, performance and integrity criteria, and identification of records # Competence, such as knowledge, skills, experience, and qualifications # Soft elements, such as personnel, integrity, confidence, organizational culture, motivation, team spirit, and quality relationships. Inspection is a major component of quality control, where physical product is examined visually (or the end results of a service are analyzed). Product inspectors will be provided with lists and descriptions of unacceptable product defects such as cracks or surface blemishes for example. History and introductio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
