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

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 （）.

變量數(shù)列中，各組頻率之和應（）

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？（）

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 （）

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

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（）

常用的長期趨勢測定的方法有哪些？各有什么特點？

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 （）.