Thirty patients with acne volunteer to be treated with either a medicinal lotion
or a normal moisturizing cream. this type of experimental design is called
a(n)
a. in vitro observation
b. clinical trial
c. geographical cohort study
d. general population survey

Thirty patients with acne volunteer to be treated with either a medicinal lotion

or a normal moisturizing cream. This type of experimental design is called

a clinical trial.-B.

the answer is; comparing the frequency of collisions with and without the device

this makes the anti-collision system an independent variable and the collisions a dependent variable. if there are fewer collisions with an anti-collision system that without, then it can be stated that the system is a success. essentially, collisions under an anti-collision system are compared with the frequency of collisions by cars with the human drivers.