I have a multifactor dataset with the variables "genotype" (2 levels) and "treatment" (2 levels). To ask the question "what genes respond differently to treatment based on genotype?" we have the following contrast:
Interact_Strain.Exposure = ((control.GenotypeA - treatment.GenotypeA) - (control.GenotypeB - treatment.GenotypeB))
However, we would also like to ask "what genes respond similarly to treatment based on genotype?".
How would we make this comparison?
Thanks for your help!