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

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 （）.

如果居民按報告期價格購買商品需多支出40萬元，報告期商品銷售額為200萬元，則價格指數為（）

A cumulative frequency distribution would provide（）.

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？

以2000年a0為最初水平，2016年an為最末水平，計算鋼產量的年平均發(fā)展速度時，須開（）

什么是季節(jié)變動？研究它的意義何在？如何測定季節(jié)變動？

一個地區(qū)一定時期的商品零售額屬于（）

品合格率指標是（）