Question

Factors, Treatments, Factor Levels and Experimental Units

Experiment and production process for a new synthetic drug:

The reaction involved in the production may have a higher or lower yield, depending on the temperature and the oxygen concentration used in production. James decides to investigate the effects of combinations of three different temperatures (60°, 70° and 80°) and two different oxygen concentration levels (55% and 60%) on the yield (in mg) of the process. Ten batches of raw material will be processed at each combination of temperature and oxygen concentration.

a) Name the factors

b) The treatments?

c) By firstly considering how many levels each factor has, compute the sum of the number of levels there are for all the factors.

d) How many experimental units does the experiment require?

Answer 1

Answer a.

There are two factors in the experiment namely,

1. Temperature

2. Oxygen concentration

Answer b.

The treatments are the yields (in mg) of the process.

​​​​​​Answer c.

There are three levels of the factor temperature and two levels of the factor oxygen concentration level. So in totality there are five levels of the two factors.

Answer d.

Since there are three levels of temperature and two levels of oxygen concentration level and we require 10 batches of raw material at each combination of temperature and oxygen, so in all we require 60 experimental units.