Six Sigma Statistical Terms - III

Six Sigma Statistical Terms
EFFECT
That which was produced by a cause.

EVOLUTIONARY OPERATIONS
A DOE process used to optimize the key process input

(EVOPS)
Variables in a production environment, is usually limited to 2-3 variables, is performed over a long period of time, and is non-disruptive to the process.

EXCEL
Spreadsheet package within Microsoft Office used for data manipulation & analysis.

EXPERIMENT
A test under defined conditions to determine an unknown effect, to illustrate or verify a known law, or to establish a hypothesis. See DESIGN OF EXPERIMENT (DOE).

EXPERIMENTAL ERROR
Variation in observations made under identical test conditions. Also called residual error. The amount of variation which cannot be attributed to the variables included in the experiment.

EXPONENTIALLY WEIGHTED
A control charting method where the most current data MOVING AVERAGE (EWMA) point is weighted on an exponential basis such that older data points carry less value in calculating average. This charting technique is used to detect small shifts in process average.

FACTORS
Independent variables.

FAILURE MODE & EFFECTS
Analytical technique focused at problem prevention thru ANALYSIS (FMEA) identification of potential problems. The FMEA is a proactive tool that is used pragmatically to identify potential failure modes and their effects, to numerically rate the combined risk associated with severity, probability of occurrence and delectability and to document appropriate plans for prevention. FMEA’s can be applied to system, (application) and product design and to manufacturing and nonmanufacturing processes (i.e., services & transactional processes).

FIRST TIME YIELD
Yield that occurs in any process step prior to any rework that may be required (see Yft Symbology) to overcome process shortcomings.

FIXED EFFECTS MODEL
An experimental model where treatments are specifically selected by the researcher. Conclusions only apply to the factor levels considered in the analysis. Inferences are restricted to the experimental levels.

FLUCTUATIONS
Variances in data which are caused by a large number of minute variations or differences.

FREQUENCY DISTRIBUTION
The pattern or shape formed by the group of measurements in a distribution based on frequency of occurrence.

GAGE ACCURACY
The average difference observed between a gage under evaluation and a master gage when measuring the same parts over multiple readings.