QUESTION

A soft drink bottler is interested in obtaining more uniform fill heights in the bottles produced by his manufacturing process. The filling machine theoretically fills each bottle to the correct target height, but in practice, there is variation around this target, and the bottler would like to understand the sources of this variability better and eventually reduce it.

The process engineer can control three variables during the fill process: the percent carbonation (A), the operating pressure in the filler (B), and the bottles produced per minute or the line speed (C). The pressure and speed are easy to control, but the percent carbonation is more difficult to control during the actual manufacturing process because it varies with product temperature. For the purposes of this experiment, the engineer can control carbonation at two levels: 10 and 14 percent. She chooses two levels for pressure (25 and 30 psi) and two levels for line speed (200 and 250 bpm). She decides to run two replicates of a factorial design in these three factors, with all runs taken in random order.

 

1.What does it mean for the engineer to run two replicates of the factorial design?

2.How would the experiment be different if she planned to use repeats (instead of replicates)?

3.What is the difference between repetition and replication? How does this difference affect the type of variability we can explore in an experiment?

4.How might the engineer incorporate blocking into this experiment? What would be the advantages and disadvantages of doing so?

 

Public Answer

ZQPCQL The First Answerer