Sample Size The amount of
data the experimenter needs to answer a statistical question. Varies with
alpha risk, beta risk & the associated difference to be detected.
Sample Statistic A value
derived from a sample from a population that is used to estimate the value of a
population parameter or group characteristic.
Screening Experiments Lower
resolution designed experiments (DOE) for investigating main effects, usually
involving several factors. Screening experiments often use Fractional Factorial
Secondary Metric Used to
measure unintended consequences of process/product changes.
Shewhart The inventor
of control charts.
Shift A sudden
change in a process characteristic.
Six Sigma Motorola
Corporation originated Six Sigma during the 1980s as a quality management
methodology, strategy, and tactics to enhance customer satisfaction, employee
development, and continuously improve processes to increase corporate profits,
shareholder value, and achieve corporate excellence.
Simple Regression A method for
determining an optimal equation (least-squared difference between observed and
predicted values for the response) for a response as a function of just one
input variable: Y= b0 + b1 X + error.
Special Cause Variation Intermittent
variation attributed to assignable events. Control charts are often used to
distinguish between special cause variation and common cause variation.
Specification Limits Requirements
based on the customer requirements or expectations.
Stability of a Measurement System A measure of
the variation in accuracy or precision of a measurement system over time.
Standard Deviation The square
root of the variance.
Star and Axial Points Levels of
inputs in a Central Composite Design experiment used to determine the second
order terms in Response Surface Modeling.
Steepest Ascent or Descent A procedure
for moving along the direction or combination of input factor values that most
rapidly increases or decreases the value of the response.
Surface Plot A plot for a
Response or z-variable based on a mesh determined from two input factors, an
x-variable and a y-variable.
Taguchi Quality Philosophy The idea that
any deviation from the target imparts a loss to society.
t-Distribution Used for
determining the confidence interval for means or for determining whether two
means are significantly different. Developed by Gossett under the pseudonym
ďStudent; hence, also referred to as Studentís t-distribution.
Temporal Variation Time-to-time
Transition Action Plan The actions
required to move the project from the Black Beltís control to the functional
Treatment A single level
assigned to a single factor.
Treatment Combination An experiment
run using a set of the specific levels of each input variable.
Type I Error Finding an
imagined difference where none actually exists.
Type II Error Failing to
find a difference when one actually exists.
Value-Added An operation
that transforms the product in a way that is meaningful to the customer.
of the Business.
VOC Voice of the Customer.
of the Process.
Z-score The distance of a
particular value from the sample mean in units of standard deviations.