Need a better way to deal with stratification, e.g. #28
Description
M <- lm(height ~ sex * age * ntiles(age, n=10, format = "interval"), data = NCHS)
gmodel(M) # doesn't work
{{ message }}
M <- lm(height ~ sex * age * ntiles(age, n=10, format = "interval"), data = NCHS)
gmodel(M) # doesn't work