average plane of 3D plot
I am trying to find an average plane of a surface.my data include X, Y, Z.I run analyze->fit model->Y variable=Z, Model effects=X,Y.then i choose factor profiling-> surface profiler to see the plot+ average plane.this is my plot when i run scatterplot 3D: and this is my plot when i run fit model:there is some transformation that change my data from dome to cylinder. any idea what to do?