## 3.3 Isikhokelo imposiso Uphando iyonke

Iyonke iimpazamo uphando error = ukumelwa + iimpazamo yomlinganiselo.

Iingqinisiso ezivela kwiisesampulu zophando zihlala zingaphelelekanga. Okokuthi, ngokuqhelekileyo kukho umahluko phakathi koqikelelo olwenziwe ngophando lwesampula (umz., Ukulinganiselwa komlinganiselo wabafundi esikolweni) kunye nenani lokwenyani kubemi (umzekelo, ukuphakama okwenyani kwabafundi esikolweni). Ngamanye amaxesha ezi mpazamo zincinci kangangokuba azibalulekanga, kodwa ngamanye amaxesha, ngelishwa, zinokuba zikhulu kwaye zilungele. Kwiinzame ukuqonda, linganisa, nokunciphisa iimpazamo, ngokuthe ngcembe Abaphandi wadala, isakhelo yesu olunye sengqiqo ngenxa yokungazi ezinokuvela kuhlolo isampula:-sikhokelo imposiso survey iyonke (Groves and Lyberg 2010) . Nangona uphuhliso lwale khokelo lwaqala ngowe-1940, ndicinga ukuba linikeza iingcamango ezimbini ezibalulekileyo zophando lophando kwixesha ledijithali.

Okokuqala, isakhelo sophononongo sesiphononongo sichaza ukuba kukho ezimbini iintlobo zeziphene: ukukhethwa kunye nokuhluka . Ngokukhawuleza, i-bias iyona mpazamo echanekileyo kwaye ukungafani kukuphosakeleyo. Ngamanye amagama, cinga iimpendulo ezi-1 000 zeseshwankathelo esifanayo kunye nokujonga ukuhanjiswa koqikelelo kulezi zimpendulo ezi-1 000. I-bias yohlukwano phakathi kwentsingiselo yalezi ziqikelelo kunye nokuxabiseka kwenene. Ukwahlukana kukuhluka kwala manqaku. Yonke into ilinganayo, singathanda inkqubo engekho nhlobo kunye nohlobo oluthile. Ngelishwa, ezininzi iingxaki zangempela, ezinjalo ukungafani, iinkqubo ezincinci ezingafaniyo, ezibeka abaphandi kwisimo esinzima sokunqumanisa indlela yokulinganisela iingxaki ezibangelwa ukuhlaziywa nokuhluka. Abanye abaphandi ngokukhethekileyo banqwenela iinkqubo ezingenakulungelelaniswa, kodwa ukugxila kwengqondo eyodwa kunokuba yimpazamo. Ukuba injongo kukuvelisa uqikelelo olusondeleyo kunokwenzeka kwi nyaniso (oko kukuthi, ngeyona mpazamo encinci kunokwenzeka), ngoko ungase ube ngcono kunye nenkqubo ene-bias encinci kunye nento encinci kuneyona ukungabi namkhethe kodwa unomlinganiselo omkhulu (umfanekiso 3.1). Ngamanye amazwi, le sikhokelo impazamo survey iyonke lubonisa ukuba xa ehlolisisa iinkqubo zophando survey, kufuneka ucinge zombini bias mahluko.

Ingqwalasela yesibini eyona ngundoqo esuka kwisakhelo sophotho yolwazi, oluza kuququzelela uninzi kwesi sahluko, kukuba kukho imithombo emibini yeziphene: iingxaki ezinxulumene nobani othethayo ( ukumela ) kunye neengxaki ezinxulumene noko ufundayo kwizo ncoko ( umlinganiselo ). Ngokomzekelo, unokuba nomdla ekuqikeleleni isimo sengqondo malunga nobumfihlo be-intanethi kubantu abadala abahlala eFransi. Ukwenza oku kuqikelelwa kudinga iintlobo ezimbini ezahlukeneyo. Okokuqala, ukusuka kwiimpendulo abaphenduliweyo banikezela, kufuneka uchithe isimo sengqondo sabo malunga nobumfihlo be-intanethi (leyo ingxaki yokulinganisa). Okwesibini, ukusuka kwisimo sengqondo esiphethwe phakathi kwabaphendulayo, kufuneka unganise isimo sengqondo kubemi ngokubanzi (leyo yingxaki yokumela). Isampuli esipheleleyo ngemibandela emibi yocwaningo iza kuvelisa iziqikelelo ezimbi, njengoko kuya kuthathwa i-sampling embi ngemibuzo ye-survey. Ngamanye amazwi, uqikelelo elungileyo zifuna iindlela ezivakalayo zemilinganiselo umelo. Ngenxa yokuba imvelaphi, ndiza kuphinda ndihlolisise indlela abaphandi abaphandi abaye bacinga ngayo ngokumelwa kunye nokulinganisa kwixesha elidlulileyo. Emva koko, ndiya kubonisa indlela iingcamango malunga nokumelwa kunye nokulinganisa kunokukhokela uphando lwe-digital-age survey.