時間序列構成因素有哪些？分解的基本原理和思路是什么？

If the individual class frequency is divided by the total frequency, the result is the （）.

一個地區(qū)一定時期的商品零售額屬于（）

為什么在計算平均指標的基礎上還有必要進一步計算變異指標？

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

要了解某地區(qū)全部大學生的就業(yè)情況，那么（）

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（）

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？（）

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 （）.

對全國各鐵路交通樞紐的貨運量、貨物種類等進行調查，以了解全國鐵路貨運概況。這種調查屬于（）