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？（）

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

A summary measure that is computed from a sample to describe a characteristic of the population is called（）

某企業(yè)的生產(chǎn)計(jì)劃完成百分比采用如下分組，請(qǐng)指出哪項(xiàng)是正確的（）

企業(yè)生產(chǎn)一種產(chǎn)品需順次經(jīng)過四個(gè)車間，這四個(gè)車間的廢品率分別為1.5%、2.0%、2.0%和1.0%。該企業(yè)生產(chǎn)這種產(chǎn)品的平均廢品率是多少？

常用的長期趨勢測定的方法有哪些？各有什么特點(diǎn)？

要了解某地區(qū)全部大學(xué)生的就業(yè)情況，那么（）

一個(gè)地區(qū)一定時(shí)期的商品零售額屬于（）

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