Data 

Factual
information used as a basis for reasoning, discussion, or
calculation 
Dependent Variable


A response
variable such as y is the dependent or "response" variable where Y =
f(X_{1}...X_{N}) variable Distribution Tendency of large
numbers of observations to group themselves around some central value
with a certain amount of variation or "scatter" on either side 
Histogram 

Vertical display
of a population distribution in terms of frequencies; a formal method of
plotting a frequency distribution 
Lower Control Limit


A horizontal
dotted line plotted on a control chart which represents the lower
process limit capabilities of a process 
NonConformity 

A condition
within a unit which does not conform to some specification, standard,
and/or requirement: often referred to as a defect: any given
nonconforming unit can have the potential for more than one
nonconformity 
Normal Distribution


A continuous,
symmetrical density function characterized by a bellshaped curve such
as distribution of sampling averages 
Null Hypothesis


A tentative
explanation which indicates that a chance distribution is
operating 
Pareto Diagram


A chart which
ranks, or places in order, common occurrences 
Perturbation 

A nonrandom
disturbance 
Population 

A group of
similar items from which a sample is drawn  often referred to as the
universe 
Primary Control


Major independent
variables used in the experiment 
Probability 

The chance of
something happening; the percent or number of occurrences over a large
number of trials 
Process 

A particular
method of doing something, generally involving a number of steps or
operations 
Process
Characterization


A way to measure
process capability, or a description of the singular qualities,
features, or traits related to individual and/or collective, progressive
steps used to manufacture a product 
Process Control Chart


Any number of
types of graphs upon which data is plotted against specific control
limits 
Producibility 

The measure of
the relative ease of manufacturing a product 
Random Cause 

A source of
variation which is random: a change in the source will not produce a
highly predictable change in the response. Examples: 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 Sample 

One or more
samples randomly selected from the population 
Random Variable 

A variable which
can assume any value from a set possible values 
Random Variations 

Variation in data
which result from causes which cannot be pinpointed or controlled 
Robust 

The condition or
state in which a parameter is impervious to perturbing influence 
RolledThroughput 

The cumulative
probability of conformance with respect to process parameters 
Scatter Diagrams 

Charts which
allow the study of correlation  such as the relationship between two
variables 
Standard Deviation 

A statistical
index of variability which describes the spread 
Statistical Process
Control 

The application
of statistical methods and procedures relative to a process and a given
set of standards 
Subgroup 

A logical
grouping of objects or events which displays only random eventtoevent
variations such as the objects or events are grouped to create
homogenous groups free of special causes. By virtue of the minimum
withingroup variability, any change in the central tendency or variance
of the population will be reflected in the subgroup tosubgroup
variability 
Systematic Variables 

A pattern which
displays predictable tendencies 
Systems Producibility 

A coordinated
approach to system design optimizing the opportunity to impact design
details, given market/design/make tradeoffs, to develop an optimum
value design 
Type I (Alpha) and Type II (Beta)
Error 

Type I error is
the probability of acceptingthe alternate hypothesis when in reality the
null hypothesis is true (a tentative explanation which indicates that a
chance distribution is operating). Type II error is the probability of
accepting the null hypothesis when in reality the alternate is
true 
Upper Control Limit 

A horizontal line
on a control chart which represents the upper limits of process
capability 
Variation 

Any quantifiable
difference between individual measurements such as the fact that
differences can be classified as being due to common (random) causes or
special causes (assignable) 
XBar and R Charts 

A control chart
which is a representation of process capability over time 
displays 