最能反映離散程度的指標(biāo)是（）

對(duì)全國(guó)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(guó)鐵路貨運(yùn)概況。這種調(diào)查屬于（）

什么是季節(jié)變動(dòng)？研究它的意義何在？如何測(cè)定季節(jié)變動(dòng)？

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

企業(yè)生產(chǎn)一種產(chǎn)品需順次經(jīng)過(guò)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？

Descriptive statistics deals with methods of（）

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

時(shí)間序列構(gòu)成因素有哪些？分解的基本原理和思路是什么？

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 cumulative frequency of the third class？（）