In a bid to arrest accelerated deterioration, the owner of a large network of steel railway bridges considering the adoption of Ultrex, a patented coating material, for spray application on all 3520 steel bridges in the state. You have been consulted to design a statistical experiment to ascertain the effectiveness of this treatment.
a. How would you design the sampling process for the experiment?
b. What are some of the precautions you would take to ensure that you have a good sample and also to minimize possible bias in the study conclusions?