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 （）.

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（）

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

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

什么是季節(jié)變動？研究它的意義何在？如何測定季節(jié)變動？

對某班級學生的生活狀況進行統(tǒng)計調(diào)查，下列標志中屬于不變標志的是（）

A cumulative frequency polygon is also called （）.

品合格率指標是（）

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？（）

A cumulative frequency distribution would provide（）.