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)？

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？（）

Descriptive statistics deals with methods of（）

在組距數(shù)列中，下限就是（）

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

Which of the following is best to show the percentage of a total budget that is spent on each category of items？（）

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

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

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 （）.

A cumulative frequency polygon is also called （）.