在組距數(shù)列中，下限就是（）

Which of the following statements is not true？（）

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？（）

品合格率指標(biāo)是（）

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

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（）

時間序列構(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 （）.

某班的學(xué)習(xí)按考試成績分為60分以下，60-70，70-80，80-90，90-100，這種分組（）

常用的長期趨勢測定的方法有哪些？各有什么特點？