李同学2019-02-07 18:40:48

A mutual fund manager wants to create a fund based on a high-grade corporate bond index. She first distinguishes between utility bonds and industrial bonds; she then, for each segment, defines maturity intervals of less than 5 years, 5 to 10 years, and greater than 10 years. For each segment and maturity level, she classifies the bonds as callable or noncallable. She then randomly selects bonds from each of the subpopulations she has created. For the manager’s sample, which of the following best describes the sampling approach? A Stratified random. B Simple random. C Systematic. 上一题  正确答案A 您的答案B 本题平均正确率：92% Sampling, time-series and cross-sectional data难度：一般 推荐：      答案解析 In stratified random sampling, one divides the population into subpopulations and randomly samples from within the subpopulations. 请问： 1.分层是一定要求每组中有固定比例吗？ 2.系统抽样是每组中第Kth个的那种吗？