Six Sigma Statistical Terms - VII

Six Sigma Statistical Terms
PROBABILITY
The chance of an event happens or condition occurring by pure chance and is stated in numerical form.

PROBABILITY OF AN EVENT
The number of successful events divided by the total number of trials.

PROBLEM
A deviation from a specified standard.

PROBLEM SOLVING
The process of solving problems; the isolation and control of those conditions which generate or facilitate the creation of undesirable symptoms.

PROCESS
A particular method of doing something, generally involving a number of steps or operations.

PROCESS AVERAGE
The central tendency of a given process characteristic across a given amount of time or at a specific point in time.

PROCESS CONTROL
See STATISTICAL PROCESS CONTROL.

PROCESS CONTROL CHART
Any of a number of various types of graphs upon which data are plotted against specific control limits.

PROCESS MAP A detailed step-by-step pictorial sequence of a process showing process inputs, potential or actual controllable and uncontrollable sources of variation, process outputs, cycle time, rework operations, and inspection points.

PROCESS SPREAD
The range of values which a given process characteristic displays; this particular term most often applies to the range but may also encompass the variance. The spread may be based on a set of data collected at a specific point in time or may reflect the variability across a given period of time.

PRODUCERS RISK
Probability of rejecting a lot when, in fact, the lot should have been accepted (see ALPHA RISK).

PROJECT
A problem, usually calling for planned action.

QUALITY FUNCTION QFD
Is a disciplined matrix methodology used for

DEPLOYMENT (QFD)
Documenting customer wants and needs – “the voice of the customer” – into operational “requirement” terms. It is an effective tool for determining critical-to-quality characteristics for transactional processes, services and products.

R CHART
Plot of the difference between the highest and lowest in a sample. Normally associated with the range control portion of an X, R chart.

RANDOM CAUSE
A source of variation which is random, usually associated with the “trivial many” process input variables, and which will not produce a highly predictable change in the process output 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