Example 1 (2004 National College Entrance Examination Hunan Paper) A company has 150, 120, 180, and 150 sales outlets in regions A, B, C, and D, respectively. To investigate the sales of its products, the company needs to draw a sample of 100 from these 600 sales outlets, which is recorded as (1); In region C, there are 20 super-large sales outlets, from which 7 need to be selected to investigate their sales revenue and after-sales service, etc., which is recorded as (2). Then, the sampling methods suitable for completing (1) and (2) are ( ).
A. Stratified sampling method, systematic sampling method
B. Stratified sampling method, simple random sampling method
C. Systematic sampling method, stratified sampling method
D. Simple random sampling method, stratified sampling method
Solution: Choose B. Reason: For different characteristics of the population, different sampling methods should be adopted. In this question, the population for survey (1) consists of sales points in four regions: A, B, C, and D, which falls under the category of a "population composed of several distinctly different parts." Therefore, for survey (1), stratified sampling should be used. For survey (2), the population consists of only 20 individuals, and a sample of size 7 needs to be drawn. This belongs to the scenario where the number of individuals in the population is relatively large, and individuals can be drawn one by one from the population, so simple random sampling should be used.