最能反映離散程度的指標是（）

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 （）.

品合格率指標是（）

變量數(shù)列中，各組頻率之和應(yīng)（）

A cumulative frequency distribution would provide（）.

某企業(yè)的生產(chǎn)計劃完成百分比采用如下分組，請指出哪項是正確的（）

One advantage of a stem and leaf plot over a frequency distribution is that （）.

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 cumulative frequency of the third class？（）

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 （）.

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