Statistics Glossary - R

Randomness

A condition in which individual values are not predictable although they may come from a definable source.

Range

The disserence between the highest and lowest values in a subgroup.

Run

A consecutive number of points:


Consistently increasing or decreasing

Consistently above or below the center line.

Can be evidence of the existence of Special causes of variation.

Runs of 7

A run of 7 consecutive points. Typically indicates an out-of-control condition.

Run Chart

A simple graphic representation of a characteristic of a process, showing plotted values of some statistic gathered from the process (often individual values) and a central line (often the median of the values) which can be analyzed for runs.

Sample

In process control applications, a synonym with Subgroup. This use is totally different from the purpose of providing an estimate of a larger group of people, items, etc.

Sigma = s

The Greek letter used to designate Standard Deviation.

Special Cause

A source of variation that is intermittent, unpredictable, unstable. Sometimes called an Assignable cause. It is signaled by a point outside a control limit or a run or other non-random pattern of points within the control limits.

Specification

The engineering requirement for judging acceptability of a particular characteristic. A specification is never to be confused with a control limit.

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The Juran Trilogy	The Deming PDCA Cycle	QMS Implementation	FMEA Information	APQP Information
Auditing Information	8-D Problem Solving	Statistics	Error Proofing (Poka Yoke)	Brainstorming
Identifying Waste	Pull Systems	Lead Time Reduction	Planned Maintenance	Quick Setup
Discovering Change	Process Capability - Cp vs. Cpk	Histogram Animation	Process Loop Animation	Taguchi Loss Function
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