1 Recall that in analytical surveys, the factor levels cannot be assigned to units (e. CHAPTER 9.

1 Recall that in analytical surveys, the factor levels cannot be assigned to units (e.g. CHAPTER 9. TWO FACTOR DESIGNS - SINGLE-SIZED EXPERIMENTAL UNITS - CR AND RCB DESIGNS examine only factorial treatment structures, i.e. every treatment combination appears somewhere in the experiment. For example, if Factor A has 2 levels, and Factor B has 3 levels, then all 6 treatment combinations appear in the experiment. Why factorial designs? Why do we insist on factorial treatment structures?