So sánh phương pháp

	Lấy mẫu ngẫu nhiên đơn giản	Chọn mẫu hạn ngạch
Lĩnh vực	Phương pháp luận khảo sát	Phương pháp luận khảo sát
Họ	Process / pipeline	Process / pipeline
Năm ra đời	Early 20th century; systematized by Cochran 1953/1977	1930s
Người khởi xướng	William Gosset, Jerzy Neyman, and formalized by William Cochran	Developed in market research and opinion polling, notably applied by George Gallup in the 1930s
Loại	Probability sampling design	Non-probability sampling design
Công trình gốc	Cochran, W. G. (1977). Sampling Techniques (3rd ed.). John Wiley & Sons. ISBN: 978-0471162407	Moser, C. A., & Kalton, G. (1972). Survey Methods in Social Investigation (2nd ed.). Heinemann. ISBN: 978-0435827496
Tên gọi khác	SRS, unrestricted random sampling, equal-probability sampling, EPSEM	quota-controlled sampling, quota selection, non-probability quota sampling
Liên quan	6	5
Tóm tắt	Simple random sampling (SRS) is the foundational probability sampling method in which every unit in the population has an equal and independent chance of being selected. Because selection is governed purely by chance, SRS eliminates systematic bias, supports unbiased estimation of population parameters, and provides the statistical baseline against which all more complex probability designs are evaluated.	Quota sampling is a non-probability technique in which the researcher pre-specifies how many units to recruit from each subgroup (quota cell) defined by one or more control variables such as age, gender, or occupation. Interviewers or data collectors then use their own judgment to find and enroll participants until each cell is filled. The method guarantees the sample mirrors the population on the control variables but does not provide the randomness needed for classical statistical inference.