Which of the answers is most suitable regarding a follow-up experiment after the result you obtained from the experiment.

Select one:

a.

A second experiment should be run using an 8 run factorial design with the three factors Discount, Advertising Channel and Message type confirm the results.

b.

The fractional factorial randomized design does allows a causal interpretation of Discount and Advertising Channel but not the interaction.

c.

A 16 run full factorial design is necessary to resolve confounding and allow causal interpretation.

d.

All answers are correct.

e.

The randomized 2-level fractional factorial design allows a causal interpretation regardless of confounding.