R CHARTS Plot of the difference between the highest and lowest in a sample. Range control chart.
RANDOM Selecting a sample so each item in the population has an equal chance of being selected; lack of predictability; without pattern.
RANDOM CAUSE A source of variation which is random; a change in the source ("trivial many" variables) will not produce a highly predictable change in the response (dependent variable), e.g., a correlation does not exist; any individual source of variation results in a small amount of variation in the response; cannot be economically eliminated from a process; an inherent natural source of variation.
RANDOM EFFECTS MODEL Experimental treatments are a random sample from a larger population of treatments. Conclusions can be extended to the population. Interference's are not restricted to the experimental levels.
RANDOM SAMPLE One or more samples randomly selected from the universe (population).
Random Sampling The process of selecting units for a sample of size, so that all units have an equal chance of being selected as the sample.
RANDOM VARIABLE A variable which can assume any value from a set of possible values.
RANDOM VARIATIONS Variations in data which result from causes which cannot be pinpointed or controlled.
RANDOMNESS A condition in which any individual event in a set of events has the same mathematical probability of occurrence as all other events within the specified set, i.e., individual events are not predictable even though they may collectively belong to a definable distribution.
RANGE The difference between the highest and lowest values in a set of values or "subgroup."
Range chart Control chart in which the range of the subgroup is used to track the instantaneous variation within a process, i.e. the variation in the process at any one time, when many input factors would not have time to vary enough to make a detectable difference. Range charts are usually paired with average charts for complete analysis.
RANKS Values assigned to items in a sample to determine their relative occurrence in a population.
Rapid prototyping. A structured software requirements discovery technique which emphasizes generating prototypes early in the development process to permit early feedback and analysis in support of the development process. Contrast with incremental development, spiral model, waterfall model. See: prototyping.
RATIO Numeric scale which has an absolute zero point and equal units of measure throughout, i.e., measurements of an output parameter, i.e., amps.
Real time processing. A fast-response [immediate response] on-line system which obtains data from an activity or a physical process, performs computations. and returns a response rapidly enough to affect [control] the outcome of the activity or process; ~g., a process control application. Contrast with batch processing.
Real time. (IEEE) Pertaining to a system or mode of operation in which computation is performed during the actual time that an external process occurs, in order that the computation results can be used to control. monitor, or respond in a timely manner to the external process. Contrast with batch. See: conversational, interactive.
Recognition The formal and informal acknowledgement of an individual or group
record of change. Documentation of changes made to the system. A record of change can be a written document or a database. Normally there are two associated with a computer system, hardware and software. Changes made to the data are recorded in an audit trail.
Record. (1) (ISO) a group of related data elements treated as a unit. [A data element (field) is a component of a record, a record is a component of a file (database)].
Recorder The team member that takes minutes during team meetings to capture team's progress. Once the team is well underway, this role can be rotated through out the group.
Redesign Business Process Redesign (BPR) The transformation of a business process to achieve significant levels of improvement in one or more performance measures relating to fitness for purpose, quality, cycle times, and cost by using the techniques of streamlining and removing non value added activities and costs
Registered Suppliers Registered Suppliers are suppliers who have received third party registration to a specific quality system standard for the commodity supplied.
Regrade Action taken on non-conforming product that changes the classification, or category of the product for use in alternative applications. Cannot be done without customer approval/direction. [Also see Repair/Rework]
Regression analysis A statistical technique used to determine the best mathematical expression to describe the relationship between a response and independent variables.
regression analysis and testing. (IEEE) A software V&V task to determine the extent of V&V analysis and testing that must be repeated when changes are made to any previously examined software products. See: testing, regression.
REGULAR PROBLEM ELIMINATION TEAM A group formed by individuals or work groups to address problems keeping them from a defect free standard or to spawn continuous work process improvements.
REJECT REGION The region of values for which the alternate hypothesis is accepted.
relational database. Database organization method that links files together as required. Relationships between files are created by comparing data such as account numbers and names. A relational system can take any two or more files and generate a new file from the records that meet the matching criteria. Routine queries often involve more than one data file; e.g., a customer tile and an order file can be linked in order to ask a question that relates to information in both tiles, such as the names of the customers that purchased a particular product. Contrast with network database, flat tile.
Relations Diagram method is a technique developed to clarify intertwined causal relationships in a complex situation in order to find an appropriate solution. It is typically represented graphically as squared ellipses (concepts) connected by directed lines (arrowheads show direction). The directed lines represent causal relations between the concepts.
Release. (IEEE) The formal notification and distribution of an approved version. See: version.
Reliability assessment. (ANSI/IEEE) The process of determining the achieved level of reliability for an existing system or system component.
Reliability The probability of a product or service successfully doing its job under given conditions.
Reliability The probability that an item will continue to function at customer expectation levels at a measurement point, under specified environmental and duty cycle conditions.
reliability. (IEEE) The ability of a system or component to perform its required functions under stated conditions for a specified period of time. See: software reliability.
Repair Action taken on non-conforming product so that the product will fulfill the intended usage, although the product may not conform to the original requirements. [Also see Regrade/Rework]
REPLICATION Observations made under identical test conditions.
REPRESENTATIVE SAMPLE A sample which accurately reflects a specific condition or set of conditions within the universe.
Requirement. (IEEE) (1) A condition or capability needed by a user to solve a problem or achieve an objective (2) A condition or capability that must be met or possessed by a system or system component to satisfy a contract, standard. specification, or other formally imposed documents. (3) A documented representation of a condition or capability as in (1) or (2). See: design requirement, functional requirement, implementation requirement, interface requirement, performance requirement, physical requirement.
Requirements analysis. (IEEE) (1) The process of studying user needs to arrive at a definition of a system, hardware, or software requirements. (2) The process of studying and refining system, hardware, or software requirements. See: prototyping, software engineering.
Requirements phase. (IEEE) The period of time in the software life cycle during which the requirements, such as functional and performance capabilities for a software product, are defined and documented.
RESEARCH Critical and exhaustive investigation or experimentation having for its aim the revision of accepted conclusions in the light of newly discovered facts.
RESIDUAL ERROR See EXPERIMENTAL ERROR.
Resources-those items necessary for a team to understand a problem and implement solutions; also, the time to work on solutions, access to manufacturing engineers, etc.
revalidation. Relative to software changes, revalidation means validating the change itself, assessing the nature of the change to determine potential ripple effects, and performing the necessary regression testing.
Review. (IEEE) A process or meeting during which a work product or set of work products, is presented to project personnel, managers, users, customers, or other interested parties for comment or approval. Types include code review, design review, formal qualification review, requirements review, test readiness review. Contrast with audit, inspection. See: static analysis.
Rework Action taken on non-conforming product so that it will meet the specified requirements.
RFP Request For Proposal
RFQ Request For Quotation
Risk assessment. (DOD) A comprehensive evaluation of the risk and its associated impact.
Risk The possibility of loss, injury, disadvantage or destruction. Apply this definition to the issues of program management and you have the starting point for successful risk management
Risk. (IEEE) A measure of the probability and severity of undesired effects. Often taken as the simple product of probability and consequence.
ROBUST The condition or state in which a response parameter exhibits hermetically to external cause of a nonrandom nature; i.e., impervious to perturbing influence.
Robust design An approach to the planning of new products and services that harnesses Taguchi methods.
Robust The ability of a product or service to function appropriately regardless of external conditions and other uncontrollable factors.
ROOT CAUSE A factor that, if changed or removed, will permanently eliminate a non conformance.
Root Cause Analysis Using one or more various tools to determine the root cause of a specific failure.
Root Cause The lowest level cause of a failure, or variation in a product, component, or process .
RPN Risk Priority Number (ref: FMEA)
Run 1) SPC: A consecutive number of points consistently increasing or decreasing. 2) Production: The production of a specified number of sequential units.
Run Chart A simple graphic representation of a characteristic of a process .
Run chart Also known as a line chart, or line graph. A chart that plots data over time, allowing you to identify trends and anomalies.
Run Chart shows the history and pattern of variation. It is helpful to indicate on the chart whether up is good or down is good. This tool is used at the beginning of the change process to see what the problems are. It is used at the end (check) part of the change process to see whether the change has resulted in a permanent improvement
Run-at-rate The rate set for normal production of a product, unit or component.