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

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

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(kāi)（）

企業(yè)生產(chǎn)一種產(chǎn)品需順次經(jīng)過(guò)四個(gè)車間，這四個(gè)車間的廢品率分別為1.5%、2.0%、2.0%和1.0%。該企業(yè)生產(chǎn)這種產(chǎn)品的平均廢品率是多少？

A cumulative frequency distribution would provide（）.

為什么在計(jì)算平均指標(biāo)的基礎(chǔ)上還有必要進(jìn)一步計(jì)算變異指標(biāo)？

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

A cumulative frequency polygon is also called （）.

If data are grouped into intervals and the number of items in each group is listed, this could be called a （）

某企業(yè)的生產(chǎn)計(jì)劃完成百分比采用如下分組，請(qǐng)指出哪項(xiàng)是正確的（）