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

要了解某地區(qū)全部大學生的就業(yè)情況，那么（）

如果居民按報告期價格購買商品需多支出40萬元，報告期商品銷售額為200萬元，則價格指數為（）

Descriptive statistics deals with methods of（）

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

品合格率指標是（）

變量數列中，各組頻率之和應（）

什么是季節(jié)變動？研究它的意義何在？如何測定季節(jié)變動？

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 （）.

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). Personnel records of 50 employees are selected for analysis. (The plant employs 250.) For this study, the average number days absent for these 50 employees is a （）.