Factorial design

An efficient design for experiments with two or more factors uses each possible combination of factor levels (called treatments) in the same number of experimental units. The repeat measurements for each treatment are called replicates and the design is called a factorial design.

The design on the previous page was an example of a factorial design for two factors but similar designs are also used for three or more factors.

  Factor C
  C1   C2
        Factor B               Factor B      
  Factor A   B1 B2   B1 B2
A1 527
561
456
377
  475
466
296
325
A2 621
664
426
476
  561
540
301
235
A3 724
743
460
426
  626
682
322
304