单选题
Which of the following is a priori probability?
A. On a random draw, the probability of choosing a stock of a particular
industry from the S＆P 500.
B. A politician's opinion concerning a recession prior to an election.
C. For a stock, based on prior patterns of up and down days, the probability
of the stock having a down day tomorrow.
【正确答案】
A
【答案解析】A priori probability is based on formal reasoning and inspection. Given the number of stocks in the airline industry in the S&P500 for example, the priori probability of selecting an airline stock would be that number divided by 500.