最能反映離散程度的指標是（）

在組距數列中，下限就是（）

品合格率指標是（）

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（）

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？

A student achieves an 82 on the first test in a statistics course. From this, she assumes that her average at the end of the semester (after other tests) will be about 82. This is an example of （）.

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). The average number of absences per employee, calculated from the personnel data of all employees, is a （）.

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 approximate range of the number of phone calls arriving each hour？（）

某企業(yè)2018年技術工占50%，2019年新招收了一批學徒工，使學徒工的比重增加了10%。假定全廠各級工資水平均無變化，則2019年職工總平均工資將（）