Question

1. in stratified sampling, how are strata defined?

a. by randomly dividing the population
b. by selecting every nth member to form a stratum
c. by the geographical location of members
d. by characteristics shared within each group

Explanation:

Stratified sampling divides the population into subgroups (strata) based on shared characteristics. Random division (a) is simple random sampling. Selecting every nth member (b) is systematic sampling. Geographical location (c) is too narrow as strata can be based on various shared traits like age, income etc., not just geography.

Answer:

d. By characteristics shared within each group