单选题 A random variable that has a countable number of possible values is called a:

A、

A. discrete random variable.
B、

B. continuous random variable.
C、

C. probability distribution.

【正确答案】 A

【答案解析】A discrete random variable is one for which the number of possible outcomes are countable, and for each possible outcome, there is a measurable and positive probability. A continuous random variable is one for which the number of outcomes is not countable.