如果居民按報(bào)告期價(jià)格購(gòu)買(mǎi)商品需多支出40萬(wàn)元，報(bào)告期商品銷(xiāo)售額為200萬(wàn)元，則價(jià)格指數(shù)為（）

A student achieves an 82 on the first test in a statistics course. From this, she assumes that her average at the end of the semester (after other tests) will be about 82. This is an example of （）.

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 cumulative frequency of the third class？（）

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？（）

企業(yè)生產(chǎn)一種產(chǎn)品需順次經(jīng)過(guò)四個(gè)車(chē)間，這四個(gè)車(chē)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？

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

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（）

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 cumulative frequency polygon is also called （）.