中文版:
简单随机抽样法
Simplerandomsampling
又称，单纯随机抽样。作为一种抽样方法，就是在总体单位中不进行任何分组排盾集市办读伯、排队等，完全排除任何主观的有目的的选择，采用纯粹偶然的方法从母体中选取样本。
来自这种方法更能体现宁项出总体中每个子体的机会完全相等，选出的样本与总体特性接近，是各种几率垂药比点线庆程凯久抽样中比较简便易行板挥帮践示境以都的一种方法。
为实现抽样的随360问答机化，可采用抽签、查随机数值表等办法。这说批增罪个办法的优点就抽样误差小，缺点是抽样手续比较繁杂。在实际工作中，真正做到总体中的每个个体被抽到的机会完全一样是不容易的。
简单随机抽样的特点:
①它要求被抽取样本的总体的个数是有限，这样，便于通过随机抽取的样本对总体进行分析。
②它是从总体中逐个地进行抽取。这样，便于在抽样实践中进行操作。
③它是一种不放回抽样。由于抽样实践中多采取不放回抽样，使其具有较广泛的实用性，而且由于所抽签的样本中没有被重复抽取的个体，便于进行有关游读裂息响集绝的分析和计算。
④它每一次抽取时放他端销养穿线父语总体中的各个个体有相同的可能性被抽到，从而保证了这种抽样方法的公平性。
Instatistics,asimplerandomsampleisasubsetofindividuals(asample)chosenfromalargerset(apopulation).Eachindividualischosenrandomlyandentirelybychance,suchthateachindividualhasthesameprobabilityo丝务雷里果章甲斤结fbeingchosenatanystageduringthesamplin声项蛋皮及日厚能读尔映gprocess,andeachsubseto货我fkindividualshasthesameprobabilityofbeingchosenforth角变故也握设esampleasanyothersubsetofkindividuals(Yates,DanielS.;Dav失左湖正养级粮训哪察idS.Moore,DarenS.Starnes(2008).ThePracticeofStatistics,3rdEd..Freeman.ISBN978-0-7167-730群斤马9-2.).Thisprocessandtechniqueisknownassimplerandomsampling,andshouldnotbeconfusedwit素杆肥笑神它加hRandomSampling.
Insmallpopulationsandofteninlargeones,suc任hsamplingistypicallydone"withoutreplacement"('SRSWOR'),i.e.,onedeliberatelyavoidschoosinganymemberofthepopulationmorethanonce.Althoughsimplerandomsamplingcan给财李住才好决雨衡第夜beconductedwithreplacementinstead,thisislesscommonandwouldnormallybedescribedmorefullyas商蛋独将很顶型频施simplerandomsamplingwithreplacement('SRSWR').Samplingdonewithoutreplacementisnolongerindependent,butstillsatisfiesexchangeability,hencemanyresultsstillhold.Further,forasmallsamplefromalargepopulation,samplingwithoutreplacementisapproximatelythesameassamplingwithreplacement,sincetheoddsofchoosingthesamesampletwiceislow.
Anunbiasedrandomselectionofindividualsisimportantsothatinthelongrun,thesamplerepresentsthepopulation.However,thisdoesnotguaranteethataparticularsampleisaperfectrepresentationofthepopulation.Simplerandomsamplingmerelyallowsonetodrawexternallyvalidconclusionsabouttheentirepopulationbasedonthesample.
Conceptually,simplerandomsamplingisthesimplestoftheprobabilitysamplingtechniques.Itrequiresacompletesamplingframe,whichmaynotbeavailableorfeasibletoconstructforlargepopulations.Evenifacompleteframeisavailable,moreefficientapproachesmaybepossibleifotherusefulinformationisavailableabouttheunitsinthepopulation.
Advantagesarethatitisfreeofclassificationerror,anditrequiresminimumadvanceknowledgeofthepopulationotherthantheframe.ItssimplicityalsomakesitrelativelyeasytointerpretdatacollectedviaSRS.Forthesereasons,simplerandomsamplingbestsuitssituationswherenotmuchinformationisavailableaboutthepopulationanddatacollectioncanbeefficientlyconductedonrandomlydistributeditems,orwherethecostofsamplingissmallenoughtomakeefficiencylessimportantthansimplicity.Iftheseconditionsarenottrue,stratifiedsamplingorclustersamplingmaybeabetterchoice.
详细的你可以去维基百科搜，还是蛮全的~~
标签：what,Simple,Random
