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 （）.

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)？

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（）

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？（）

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 （）.

品合格率指標(biāo)是（）

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？

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

一個(gè)地區(qū)一定時(shí)期的商品零售額屬于（）

對(duì)某班級(jí)學(xué)生的生活狀況進(jìn)行統(tǒng)計(jì)調(diào)查，下列標(biāo)志中屬于不變標(biāo)志的是（）