Hi All, I constructed a definitive screening design for the filtration of particles under different conditions. The particles express 3 different categorical surface types, C, R and V. There are 4 different types of filters, HA, HV, Nylon and PES. The continuous variables are pH and Salt, with centre points. My responses are particle transmission and contaminant transmission as a percentage of a non-filtered control. I initially designed the experiment with only pH and Salt with two blocks. As my experiment expanded I duplicated the same DoE for the different surface types and filters, eventually collating into one dataset and adding seperate columns to describe the new filter and surface types. From this datset I am looking to evaluate the significant factors that impact transmission, identify the best conditions for each surface type and identify the best surface type in general. I have attempted a full factorial of my categorical and continuous condtions, and response surface, but in my naivety I find reducing my model under effect summary can wildly differ my results. Thanks.
... View more