Question

Cell phone screen covers are either flexible plastic or hard plastic. An experiment is to be conducted to determine whether the swiping speed is the same for both types of screen covers. In previous studies, it was determined that cell phone size (small, medium, large) is associated with swiping speed, but cell phone type (Android, iPhone, and so on) is not associated with swiping speed. How could the experiment BEST be conducted?

a	By blocking on swiping speed
b	By blocking on screen cover type
c	By blocking on cell phone size
d	By blocking on cell phone type
e	Without blocking

Answer 1

Option C

c By blocking on cell phone size

as mentioned cell phone type is not directly associated with the cell phone type but phone size will effect swiping speed so we can block this out

Many times a factorial experiment requires so many runs that not all of them can be completed under homogeneous conditions. This may lead to the inclusion of the effects of nuisance factors into the investigation. Nuisance factors are factors that have an effect on the response but are not of primary interest to the investigator