變量數(shù)列中，各組頻率之和應(yīng)（）

品合格率指標(biāo)是（）

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 （）.

常用的長期趨勢測定的方法有哪些？各有什么特點？

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？（）

最能反映離散程度的指標(biāo)是（）

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

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 （）.

If the individual class frequency is divided by the total frequency, the result is the （）.

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