The number of class intervals in a frequency distribution is usually between （）.

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？

為什么在計(jì)算平均指標(biāo)的基礎(chǔ)上還有必要進(jìn)一步計(jì)算變異指標(biāo)？

要了解某地區(qū)全部大學(xué)生的就業(yè)情況，那么（）

以2000年a0為最初水平，2016年an為最末水平，計(jì)算鋼產(chǎn)量的年平均發(fā)展速度時(shí)，須開（）

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

對(duì)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（）

A summary measure that is computed from a sample to describe a characteristic of the population is called（）

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

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 （）.