The number of class intervals in a frequency distribution is usually between （）.

常用的長(zhǎng)期趨勢(shì)測(cè)定的方法有哪些？各有什么特點(diǎn)？

一個(gè)地區(qū)一定時(shí)期的商品零售額屬于（）

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 （）.

時(shí)間序列構(gòu)成因素有哪些？分解的基本原理和思路是什么？

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

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

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 （）.

The number of phone calls arriving at a switchboard each hour has been recorded and the following frequency distribution has been developed.What is the approximate range of the number of phone calls arriving each hour？（）

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