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

某企業(yè)2018年技術(shù)工占50%，2019年新招收了一批學(xué)徒工，使學(xué)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（）

常用的長期趨勢測定的方法有哪些？各有什么特點？

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

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？（）

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 （）.

為什么在計算平均指標的基礎(chǔ)上還有必要進一步計算變異指標？

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

變量數(shù)列中，各組頻率之和應(yīng)（）

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？