# Questions tagged [fractional-factorial]

Experimental designs that use only a subset of possible factor combinations. Typically, some factors are intentionally confounded w/ some interactions, making the interactions impossible to estimate, but requiring a smaller N for the study.

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### De-aliasing two-factor interactions in a Plackett-Burman design

what I've got so far is a 2-level experiment design with 10 factors and 32 experiments, which is made of a resolution III Plackett-Burman design that I folded (complete foldover) so that it is a ...
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### How to extend Plackett-Burman design to further explore the interactions?

My situation is as follows: I have built a 2-level Plackett-Burman design with 10 factors (some are actual 0/1-variables, the others are numeric and I used the minimum and the maximum) and 32 ...
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### Interaction Effects, Zero or non-Zero in 2 factor factorial design?

In a 2 factor factorial design it is common to use the following linear model and the associated notation: $y_{ijk}=\mu+\alpha_{i}+\beta_{j}+(\alpha\beta)_{ij}+\epsilon_{ijk}$ $(\alpha\beta)_{ij}$ ...
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### How to deciding on the number of experimental runs in R for orthogonal fractional factorial design?

Presently I am working on designing a questionnaire for my discrete choice experiment. I want to generate an orthogonal fractional factorial design for the following problem- The respondent has to ...
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### Is there value in assigning a dimension-specific weighting when calculating the main effect?

I've been looking into factorial designs and noticed an interesting property. Is this simply a mathematical trick or can we attribute some 'meaning' to it? Say we have a $2^k$ design where k = 3 here....
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### Why is there aliasing in a full-factorial design?

I am using the R package AlgDesign to evaluate the design of a simple full-factorial experiment, tweaking an example from R Bloggers. I've specified ...
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### Bayesian updating of log-normal parameter after observation of poisson process

I am trying to update my estimate of a parameter (error rate) which has a prior log-normal distribution using an observation of errors (presumed to be Poisson distributed). However, I am having some ...
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### Do I want a mixed model for fractional factorial designs?

I have created a d-efficient fractional factorial design of 48 combinations from a total of 192 possible combinations (4x2x2x3x2x2). For the experiment, I plan to have 4 runs in 12 blocks and 40 ...
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### Algorithm for generating a multi-level fractional factorial design

I would like to perform some black box testing on some software that takes a large number of input variables. These variables can have some interactions (either intentional or non-intentional) so I ...
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### Optimum approximate theory D-Optimal design

I am using optFederov, from package AlgDesign, to create D-Optimial designs. However, I am a bit confused on what measure to use as efficiency measure. I'd like to use D-Optimal but I don't know which ...
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### Experimental (factorial) design not exploiting the variance

I want to construct a design to use Choice Based Conjoint Analysis. I want to focus on D-Optimality, for that reason I use the R package AlgDesign which uses Fedorov Algorithm. I create 7 attributes ...
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### How to interpret Experimental design created by AlgDesign?

I'm doing an experimental study of 5 factors with a different amount of levels in each. More specifically: 9, 13, 12, 6 & 15. Using the AlgDesign library in R, i ran the following syntax to ...
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### Machine Learning for optimization of configuration file

For my master's thesis I am using a 3rd party program (SExtractor) in addition to a python pipeline to work with astronomical image data. SExtractor takes a configuration file with numerous parameters ...
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### How to combine in a (fractional) factorial design model the blocking effect with a treatment (package planor)

For my greenhouse experiment with potted trees, I am planing a fractional factorial design. The experiment has six factors (treatments) each with two factor-levels, and I want to use a model/package, ...
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### Fractional factorial designs: lower $p$ vs. more replications

If you were to choose between a 2(X-1) with only one replication or a 2(X-2) with two replications, what would be preferred and why? The goal is to both predict the values of the effect parameters as ...
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### How do I analyze interaction in two-factor factorial data when sample size is not given?

I am looking at two-factor factorial data where the response variable is number of cancer cells after an experiment is performed. The two-factors are: Factor A, which has a = 2 levels: "...