问题
单项选择题
An analyst wants to get, crate a simple random sample of 500 stocks from all 10000 stocks traded on the New York Stock Exchange, the American Stock Exchange, and NASDAQ. Which of the following methods is least likely to generate a random sample（）
A. Listing all the stocks traded on all three exchanges in alphabetical order and selecting every. 20th stock.
B. Writing the name of each stock on a piece of paper, putting them in a hat, and drawing out 500 names, one at a time.
C. Using the 500 stocks in the S＆P 500.
答案
参考答案：C
解析：
The S＆P 500 is not a random sample of all stocks traded in the U. S. because it represents the 500 largest stocks. The other three choices are legitimate methods of selecting a simple random sample.