要了解某地区全部大学生的就业情况，那么（）

以2000年a0为最初水平，2016年an为最末水平，计算钢产量的年平均发展速度时，须开（）

If data are grouped into intervals and the number of items in each group is listed, this could be called a （）

Simon Arnett, Director of Human Resources, is exploring the causes of employee absenteeism at Buderim Bottling during the last operating year (1 January 2005 to 31 December 2005). The average number of absences per employee, calculated from the personnel data of all employees, is a （）.

If the individual class frequency is divided by the total frequency, the result is the （）.

某厂某年职工劳动生产率为20000元，是历史最高水平的1.2倍。这里的1.2倍是（）

变量数列中，各组频率之和应（）

One advantage of a stem and leaf plot over a frequency distribution is that （）.

品合格率指标是（）

Claudia Taylor, Director of Global Industrial Sales in Melbourne, is concerned by a deteriorating sales trend. Specifically, the number of customers is stable at 1500 but they are purchasing less each year. She orders her staff to search for causes of the downward trend by selecting a focus group of 40 industrial customers. For this study, the set of 40 industrial customers is a （）.