单选题 Which of the following is least likely a property of t-distribution?

A、 As the degrees of freedom get larger, the variance approaches zero.
B、 It is defined by a single parameter, the degrees of freedom, which is equal to n-1.
C、 It has more probability in the tails and less at the peak than a standard normal distribution.

【正确答案】 A

【答案解析】[解析] 如下图所示，随着自由度(样本空间n)的增大，t分布的图形无限趋近于正态分布，从而其方差逐渐趋近于正态分布的方差，而非逐渐趋于零。