時(shí)間序列構(gòu)成因素有哪些？分解的基本原理和思路是什么？

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

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 cumulative frequency of the third class？（）

品合格率指標(biāo)是（）

在組距數(shù)列中，下限就是（）

對(duì)全國各鐵路交通樞紐的貨運(yùn)量、貨物種類等進(jìn)行調(diào)查，以了解全國鐵路貨運(yùn)概況。這種調(diào)查屬于（）

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 （）.

Descriptive statistics deals with methods of（）

對(duì)某班級(jí)學(xué)生的生活狀況進(jìn)行統(tǒng)計(jì)調(diào)查，下列標(biāo)志中屬于不變標(biāo)志的是（）

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