问题
单项选择题
Which of the following is a discrete random variable（）
A. The amount of time between two successive stock trades.
B. The realized return on a corporate bond.
C. The number of advancing stocks in the DJIA in a day.
答案
参考答案：C
解析：
Since the DJIA consists of only 30 stocks, the answer associated with it would be a discrete random variable. Random variables measuring time, rates of return and weight will be continuous.