答案和详解如下： 1.The sample of per square foot sales for 100 U.S. retailers in December 2004 is an example of: A) cross-sectional data. B) unbiased data. C) time-series data. D) randomly-distributed data. The correct answer was A) Cross-sectional data are a sample of observations taken at a single point in time. A time-series is a sample of observations taken at specific and equally spaced points in time. 2.Monthly Gross Domestic Product (GDP) figures from 1990-2000 are an example of: A) systematic data. B) non-random data. C) cross-sectional data. D) time-series data. The correct answer was D) A time-series is a group of observations taken at specific and equally spaced points in time. Cross-sectional data are observations taken at a single point in time. | 
发表于 2008-4-14 14:25
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