對全國各鐵路交通樞紐的貨運(yùn)量、貨物種類等進(jìn)行調(diào)查，以了解全國鐵路貨運(yùn)概況。這種調(diào)查屬于（）

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

一個地區(qū)一定時期的商品零售額屬于（）

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 （）.

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 （）.

變量數(shù)列中，各組頻率之和應(yīng)（）

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？（）

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？

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(shù)為（）