Menu.FrF2levelTab1 {RcmdrPlugin.DoE} | R Documentation |
Basic information for regular (fractional) factorial 2-level designs
Description
Basic information for regular (fractional) factorial 2-level designs
Brief statistical background
These designs are created with function FrF2
from package FrF2.
Look up the documentation there for statistical details. Users who are not
familiar with the terminology around regular fractional factorial designs (e.g.
the concept of resolution) can browse the DoEGlossary
.
Inputs on Tab Base Settings
- name of design
- must be a valid name. The design itself is created under
this name in the R workspace.
- number of runs
- must be a power of 2.
If this is omitted by unchecking the checkbox next to it, the function
looks for the smallest possible design that fulfills all requirements.
- number of factors
- must always be specified. It must be smaller than
the number of runs. Resolution IV designs are possible, if this number is
smaller than half the number of runs.
- replications
- is the number of times each experimental run is conducted.
If larger than 1, each run is conducted several times. If the checkbox next
to the number of replications is checked, it is assumed that the experiment
involves repeated measurements for one setup of the experimental run; if it
is not checked, the experimental run itself is replicated with everything
relevant newly set up (much more valuable than repeated measurements, unless
the key driver of variability is in the measuring step). If the check box is
not checked, the experiment will be randomized separately for each round of
replications (first all first runs, then all second runs etc.).
- blocks
- is the number of blocks. Blocks are needed, if a factor relevant to
the outcome but not of interest in itself is to be corrected for (e.g. batch
of material). If you just give a number here, the program takes care of
all details itself. If you are an expert and consider it necessary,
you can provide more information on the
special tab on blocking that is visible if special choices have been activated.
- randomization settings
- should normally not be changed; you can provide a
seed if you want to exactly reproduce a randomized design created in the past.
Unchecking the randomization box will produce a non-randomized experiment.
This is usually NOT recommended.
- Design Properties
- allow to set a minimum resolution (III, IV or V+);
for most purposes, IV is a good solution, i.e. it might be a good idea to
increase the default choice.
In addition, a choice can be made between
MA = maximum resolution and minimum aberration,
which implies usage of the design with the
overall least severe degree of aliasing among effects,
OR
MaxC2 = maximum number of clear 2-factor interactions, which means that the
design is chosen for which the most 2-factor interactions are not aliased with
any other main effect or 2-factor interaction.
Note that, when choosing MaxC2, it is particularly important to also
consider setting resolution to IV, as otherwise the design will very likely
be of resolution III only, even if there are good resolution IV designs with
many clear 2-factor interactions around.
- Information Buttons
- are available for looking at interim information on the
suitable designs: The button
View available designs
allows to
look at the properties of the designs in the catalogue, the button
Show best 10 designs ...
prints more detailed information on the best
10 available designs for the currently specified settings.
Note that you may want to retrieve the still open menu from somewhere
in case the latter button is used, since this button releases the grab on the menu
in support of scrollability of the printed results. I hope to find a better solution
for this in the future.
- Expert Choices
- If the special choices are activated, it is possible to
pick a design name from the catalogue of designs or to
specify a set of generators.
Details for these choices can be found in the help file for function
FrF2
.
Author(s)
Ulrike Groemping
See Also
See also FrF2
for the function that does the calculations,
catlg
for the catalogue of designs that this functionality is based on,
and Menu.2level
for the distinction between screening designs and regular
fractional factorial designs.
[Package
RcmdrPlugin.DoE version 0.6-10
Index]