What is factorial regression?
To simplify matters, full-factorial regression designs are defined as designs in which all possible products of the continuous predictor variables are represented in the design.
What does a factorial design tell us?
Factorial designs allow researchers to look at how multiple factors affect a dependent variable, both independently and together. Factorial design studies are named for the number of levels of the factors. A study with two factors that each have two levels, for example, is called a 2×2 factorial design.
What is factorial design used for?
A factorial design is necessary when interactions may be present to avoid misleading conclusions. Factorial designs allow the effects of a factor to be estimated at several levels of the other factors, yielding conclusions that are valid over a range of experimental conditions.
How many main effects are in a 2×3 factorial design?
So a 2×2 factorial will have two levels or two factors and a 2×3 factorial will have three factors each at two levels.
How to design a 2 x 2 factorial design?
Here is the regression model statement for a simple 2 x 2 Factorial Design. In this design, we have one factor for time in instruction (1 hour/week versus 4 hours/week) and one factor for setting (in-class or pull-out). The model uses a dummy variable (represented by a Z) for each factor.
How is a dummy variable used in a factorial design?
The model uses a dummy variable (represented by a Z) for each factor. In two-way factorial designs like this, we have two main effects and one interaction.
Can a factorial design have more than one replication?
We have first discussed factorial designs with replications, then factorial designs with one replication, now factorial designs with one observation per cell and no replications, which will lead us eventually to fractional factorial designs.
How to create an unreplicated 2 k factorial design?
CTRL + SHIFT + F (Windows) ⌘ + ⇧ + F (Mac) These are 2 k factorial designs with one observation at each corner of the “cube”. An unreplicated 2 k factorial design is also sometimes called a “single replicate” of the 2 k experiment.