eldo_user

Statistical Experimental Design and Analysis
Factor Screening Experiments in Eldo
Factor Screening Experiments in Eldo
Eldo contains the basic tools for performing a factor screening experiment. Use the Eldo .DEX
command to perform the factor screening.
The DEX techniques incorporated in the Eldo command .DEX are efficient procedures ensuring
the data obtained can be analyzed to yield valid and objective conclusions. This efficiency is
founded on some key properties of orthogonal arrays, which offer a systematic way of testing.
The benefits include: a uniform distributed coverage of the test domain; all pair-wise
combinations of the test set are created; and you can arrive at complex combinations of all the
variables.
The procedures implemented in the DEX analysis should be qualified. The quantitative
techniques used for factor screening are incomplete since they are numeric summaries. By
reducing the data to a few numbers (filtering the data) you are omitting and screening out other,
sometimes crucial, information.
The .DEX command enables for two-level designs that have just “High” and “Low” settings for
each factor. The most popular experimental designs are two-level designs. These are ideal for
screening designs, because they are simple and economical and also give most of the
information required to go to a multilevel response surface experiment if one is needed.
Note
In two-level experiments, only the linear effects can be studied. To detect a curvature effect
three-level factors should be considered. For example, the factor “temperature” may affect
the responses in a non-monotone way. Using only two temperature levels (“High” and “Low”)
makes a strong assumption about the relationship between the responses and the temperature.
Use the following Eldo commands for experimental design:
• .PARAMDEX — Assigns values to parameters (factors) used in the design of
experiments.
• .DEX — Conducts a screening experiment. Factors are taken from the list of circuit
parameters appearing on a .PARAMDEX statement.
• viewdex — A service routine that is run on the .dex file to display the results.
Tip
For the syntax and detailed descriptions, see “.PARAMDEX” and “.DEX” in the
Eldo Reference Manual.
DEX Example Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 558
Factorial Design Comparison with Worse Case Analysis . . . . . . . . . . . . . . . . . . . . . . . . 559
Statistical Modeling for Discrete Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 560
Eldo® User's Manual, 15.3 557