Answer:
To select a stratified random sample, first classify the population into groups of similar individuals, then choose a separate SRS in each group and combine these SRS to form the full sample
Step-by-step explanation:
Stratified random sampling involved dividing the population into small groups of similar individuals (called strata) and then from among those groups, a stratified random sample is selected and then, all these samples are combined to form the full sample. Hence, the missing word in this sentence is stratified.