Descriptive statistics deals with methods of（）

变量数列中，各组频率之和应（）

如果居民按报告期价格购买商品需多支出40万元，报告期商品销售额为200万元，则价格指数为（）

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 （）.

某班的学习按考试成绩分为60分以下，60-70，70-80，80-90，90-100，这种分组（）

A cumulative frequency polygon is also called （）.

Which of the following is best to show the percentage of a total budget that is spent on each category of items？（）

One rule that must always be followed in constructing frequency distributions is that （）.

Which of the following statements is not true？（）