變量數(shù)列中，各組頻率之和應（）

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 （）.

如果居民按報告期價格購買商品需多支出40萬元，報告期商品銷售額為200萬元，則價格指數(shù)為（）

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（）

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

常用的長期趨勢測定的方法有哪些？各有什么特點？

Which of the following is not the goal of descriptive statistics?（）

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 （）.

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