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

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 （）.

某企业2018年技术工占50%，2019年新招收了一批学徒工，使学徒工的比重增加了10%。假定全厂各级工资水平均无变化，则2019年职工总平均工资将（）

对某班级学生的生活状况进行统计调查，下列标志中属于不变标志的是（）

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

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

The number of class intervals in a frequency distribution is usually between （）.

最能反映离散程度的指标是（）

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

Claudia Taylor, Director of Global Industrial Sales in Melbourne, is concerned by a deteriorating sales trend. Specifically, the number of customers is stable at 1500 but they are purchasing less each year. She orders her staff to search for causes of the downward trend by selecting a focus group of 40 industrial customers. For this study, the set of 40 industrial customers is a （）.