What type of sample divides the population into nonoverlapping groups of N1, N2, N3, . . . Ni, such that N1 + N2 + N3 + . . . + Ni + N = N, and then performs a simple random sample of ƒ = n/N in each of the nonoverlapping groups?
a. simple random
b. stratified random
c. systematic random
d. cluster random
b
Psychology