单选题 An analyst has recently determined that only 70 percent of all U. S. pension funds have holdings in hedge funds. In evaluating this probability, a random sample of 40 U.S. pension funds is taken. The number of U. S. pension finds in the sample of 40 that have hedge funds in their portfolio would most accurately be described as:

A、

A. multivariate random variable.
B、

B. a continuous random variable.
C、

C. a binomial random variable.

【正确答案】 C

【答案解析】This is a Bernoulli trial because a U. S. pension fund either has investments in hedge funds or it does not; i.e., the experiment must have one of two outcomes. A binomial random variable is defined as the number of successes in Bernoulli trials.