sampling at random 中文意思是什麼
sampling at random
解釋
隨機抽樣-
Sampling : grade and staple : 10 % to be sampled at random for each lot of bales ; micronaire and strength : one half of the 10 % is to be sampled at random for each bunch of bales
抽樣：品級、長度：從每批棉包中隨機抽樣10 ；馬克隆值和強度：從品級、長度抽取的樣品中隨機抽取其樣品總量的一半，作為馬克隆值和強力的檢驗樣品。 -
First, this paper gives an introduction of some methods of unequal probability sampling, their estimators and variance estimators, including sampling with pps with replacement, methods of sampling without replacement suggested by brewer, durbin, sampford, des raj, murthy, rao - hartley - cochran. then, at the basis of rao and bayless ' s study, we consider that population can be splited two random subpopulations, which are respectively drawn from different infinite super - populations, and compare the stabilities of estimators of the methods that given above. we find that the minor difference between two super - populations has great effect on the efficiency of the estimators for the population with moderately large coefficient of variation ( c. v. )
本文首先從理論上介紹了若干種不等概率抽樣方法，它們的估計量、估計量的方差及其估計，其中包括有放回ppz及pps抽樣，不放回不等概率抽樣中的brewer 、 durbin 、 sampford 、 desraj ， murthy 、 rao - hartley - cochran等人的方法；其次，在rao和bayless兩人就樣本單元數n = 2的情形對上述抽樣方法進行比較的基礎上，將總體隨機地分成兩個子總體，視每個子總體取自不同的線性超總體，在文中，我們利用計算機實現隨機分組，並通過畫圖比較各方法估計量的穩定性，結果表明，對變異系數c . v . （ x ）較大的總體而言，兩個超總體之間的微小差異將對估計量的穩定性產生很大的影響，從而說明rao和bayless的比較結果還不夠完善。 -
At the other end of the spectrum, high - error - rate ( 4 percent ) random sampling of the genome has proved useful for discovery and classification of various rna and tissue types
從另一角度來看，對基因組隨機取樣定序，即使誤差高（ 4 % ） ，卻對發現和區分各種rna和組織類型極為有用。 -
The study used a stratified random sampling method to look at 2159 junior high school students from 22 schools of 6 counties of northern taiwan, as well as 475 inmates of juvenile correctional institutions ; thus there were a total of 2634 samples
在幫派入侵校園部分，樣本反映出校內常有幫派分子活動，少數學生反應受到幫派學生的侵害，約有11 %的學生指出，恐懼校內外幫派分子之侵擾。
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