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 （）.

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

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

要了解某地區(qū)全部大學生的就業(yè)情況，那么（）

某企業(yè)的生產(chǎn)計劃完成百分比采用如下分組，請指出哪項是正確的（）

一個地區(qū)一定時期的商品零售額屬于（）

Which of the following is not the goal of descriptive statistics?（）

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

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

企業(yè)生產(chǎn)一種產(chǎn)品需順次經(jīng)過四個車間，這四個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？