Factorial Design:

The factorial  experiment design  allows  the researcher to test two  or more  variables  at the same  time. It  determines whether  the variables interact to produce  an observed response or whether the variables operate independently to  produce the response. The factorial experiment is used when  there are three or more experimental variables. It is  applied when  the design is completely randomized or is a randomized block or Latin square. The main  feature of this  design is that the impact of various variables can be examined. It  involves some complex computations. We can calculate the interaction of the variables on each other which  requires variance analysis and notching out the  main  effects of each of the  variables. Standard deviation and mean squares are calculated to fin doubt the impact of   variables. Thus  this design  determines not only  the main  effects of each of the variable but  also measures the interaction effects of the variables. For  example  the use of coffee may  be preferred  with a high  content of sugar  and high  flavour. To test these  contents  various doses  of sugar  may be  introduced and the number of consumers purchasing them may  be recorded  to find out their consequences.