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

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

什么是季節(jié)變動(dòng)？研究它的意義何在？如何測定季節(jié)變動(dòng)？

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 （）.

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

A cumulative frequency polygon is also called （）.

一個(gè)地區(qū)一定時(shí)期的商品零售額屬于（）

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

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 （）.