Answer:
Quota Sampling
Explanation:
Quota Sampling is a non-probability sampling method in research, where the researcher forms subgroups of individuals who are representative of the entire population through random selection. Quota sampling is often used by researchers who want to get an accurate representation of the entire population. It saves time and money especially if accurate samples are used.
In the example given above, where the research creates subgroups of 30 pre-school children by dividing them into 10 two-year-old children, 10 three-year-old, and 10 four-year-old children, he has applied the quota sampling. These subgroups would give a proper representation of the preschool children in local daycare centers.