单选题 A set of rules used to select a sample is most likely described as:
A. sampling plan.
B. sampling error.
C. sample statistic.

【正确答案】 A

【答案解析】[解析] 样本计划(sampling plan)是选择一组样本的规则。样本误差(sampling error)是样本均值和总体均值之间的差。样本统计(sample statistic)是统计和研究样本中的数据。