So sánh phương pháp

	Lấy mẫu ngẫu nhiên đơn giản theo tỷ lệ	Lấy mẫu có trọng số
Lĩnh vực	Phương pháp luận khảo sát	Phương pháp luận khảo sát
Họ	Process / pipeline	Process / pipeline
Năm ra đời	Mid-20th century (formalized ~1950s–1970s)	1940s–1952 (formalized in large-scale government survey work and the Horvitz-Thompson estimator)
Người khởi xướng	William G. Cochran and survey statisticians (classical probability sampling tradition)	Morris H. Hansen, William N. Hurwitz; D. G. Horvitz and D. J. Thompson (theoretical framework)
Loại	Probability sampling technique	Probability sampling design
Công trình gốc	Cochran, W. G. (1977). Sampling Techniques (3rd ed.). John Wiley & Sons. ISBN: 978-0471162407	Cochran, W. G. (1977). Sampling Techniques (3rd ed.). John Wiley & Sons. ISBN: 978-0471162407
Tên gọi khác	proportional SRS, probability-proportional simple random sampling, proportional random sampling	probability proportional to size sampling, PPS sampling, unequal probability sampling, importance sampling
Liên quan	6	6
Tóm tắt	Proportional simple random sampling is a probability-based sampling technique in which units are drawn at random from each subgroup of the population in numbers proportional to each subgroup's share of the total population. This ensures the resulting sample mirrors the population's composition across key subgroups, while retaining the randomness and unbiasedness of simple random sampling within each group.	Weighted sampling is a probability-based design in which units are selected with unequal probabilities proportional to a known auxiliary measure of size or importance. Sampling weights — the inverse of inclusion probabilities — are applied during analysis so that each sampled unit correctly represents the population units it stands for. The approach underpins large-scale government, health, and social surveys where simple random sampling would be inefficient.