02-01-2016 09:35 PM
Hi all: I am planning to do the analysis using Response method. I have a Question regarding coding for my independednt variables. For example : X1 , X2, X3 are the independednt coded variables, however in my cases I also have combination tretament (eg. x1+x2). Usullay for the single independednt variables coding can be done as 1, 0, -1. I am very new to the programm so would like to get information on how the coding is done for combination treatment effect? Thank you so much and hope the way I am putting question make sense.
Example of the scinario:
Treatment 1: effect of Acid on bacterial growth
Treat 2: Effect of Protein on bacterial growth
Treat 3: Effect of Acid+protein on bacterial growth (How to do coding for combination/interaction effects )
02-01-2016 09:38 PM
How does that look like for your data? Are they independent variables or a single variable, treatment?
I might suggest a model as follows:
(Treatment=1)*B1 + (Treatment=2)*B2
So for scenarios:
02-02-2016 10:25 AM
02-02-2016 01:53 PM
It looks like they're all categorical variables, so you'll need to make indicator variables for these variables. Remember that if you have N levels you need n-1 indicators. Also, you interactions can then be specified as combinations of the other variables.