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

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

在組距數(shù)列中，下限就是（）

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？（）

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 （）.

要了解某地區(qū)全部大學(xué)生的就業(yè)情況，那么（）

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 （）.

A cumulative frequency polygon is also called （）.

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

一個(gè)地區(qū)一定時(shí)期的商品零售額屬于（）