When the population is divided into mutually exclusive sets, and then a simple random sample is drawn from each set, this is called:
a. simple random sampling.
b. stratified random sampling.
c. cluster sampling.
d. selection bias.
Question 2
A pharmaceutical company interested in measuring how often physicians prescribe a certain drug has selected a simple random sample from each of two groups: M.D. (Medical Doctors) and D.O. (Osteopaths). What is this type of sampling called?
a. Simple random sampling.
b. Cluster sampling.
c. Stratified random sampling.
d. None of these choices.