3.4.3 iisampuli Non-linokuba: ethelekisa isampulu
Ayizizo zonke iisampulu non-linokuba ziyafana. Sinako ongeze ulawulo vetshe ekupheleni ngaphambili.
Indlela Wang noogxa ingasetyenziswa ukuqikelela kwisiphumo 2012 US unyulo lomongameli kwakuxhomekeke ngokupheleleyo ngonyuselo kucazululo data. Oko kukuthi, baqokelelana iimpendulo ezininzi kangangoko unako ke ngoko uzame kwakhona ubunzima ngabo. A qhinga Incedisa zokusebenza kunye non-linokuba ukukhiwa ukuba ulawulo phezu inkqubo yokuqokelelwa kwedatha.
Umzekelo elula senkqubo isampuli non-linokuba ilawulwa ngokuyinxenye na isampuli quota, ayibobuchule ukuba sibuyele ekuqaleni uphando uphando. Xa quota isampulu, abaphandi yahlula abemi ngokwamaqela ezahlukeneyo (umzekelo, abafana, amabhinqa aselula, njl) kunye iquotas ngoko iseti inani labantu abaza kukhethwa kwiqela ngalinye. Abamangalelwa zikhetwa ngendlela engalawulekiyo de umphandi uye wadibana quota yabo kwiqela ngalinye. Ngenxa abanokubuloba, isampuli nto ujonge lwabantu ekujoliswe kunokuba bekuya kuba njalo ngenye indlela, kodwa kuba yenzekile yokubandakanywa ayaziwa abaphandi abaninzi abakholelwa le quota isampulu. Enyanisweni, quota sampulu olubangele i "Dewey koyiswa Truman" Impazamo kwi 1948 US kaMongameli ngokweentloko. Kuba inika ulawulo abanye phezu inkqubo isampulu, Noko ke, umntu uyakwazi ukubona ukuba quota isampulu abe luncedo ngaphezu ingqokelela data olungalawulwayo ngokupheleleyo.
Ukuqhubeka ngaphaya quota isampulu, iindlela zale mihla ukuba ngokulawula inkqubo isampuli non-linokuba ngoku kunokwenzeka. Enye ezo ndlela kuthiwa ethelekisa isampulu, kwaye isetyenziswa ngabanye ababoneleli yorhwebo yolawulo online. Kwindlela yayo ilula, ethelekisa isampulu kufuna imithombo yedatha ezimbini: 1) irejista ngokupheleleyo abemi kunye 2) iphaneli enkulu amavolontiya. Kubalulekile ukuba akukho mfuneko amavolontiya ukuba isampuli lemizuzu nayiphi abemi; ukugxininisa ukuba akukho mfuno yokukhetha kwiqela lenjongo, ndiza kubiza ibe yolawulo emdaka. Kwakhona, zombini irejista labemi lenjongo amdaka kufuneka ibandakanye ulwazi abangabancedani malunga umntu ngamnye, kulo mzekelo, ndiza ingqalelo ubudala ngesondo, kodwa kwiimeko olusengqiqweni olu lwazi abangabancedani kuba eneenkcukacha kakhulu. Iqhinga matching isampulu kukukhetha iisampuli evela kwiphaneli ezimdaka ngendlela evelisa iisampulu ezikhangeleka iisampulu ezinokwenzeka.
Sample ethelekisa iqala xa isampuli okwenzeka efanisiweyo ethatyathwa kwirejista abantu; Kwakule sampulu oluye iba isampulu target. Emva koko, esekelwe kwiinkcukacha abangabancedani, iimeko kwisampulu ekujoliswe abasoze abantu lenjongo elimdaka ukwenza isampulu etelekiswe. Umzekelo, ukuba kukho obhinqileyo kunyaka-25 ubudala kwisampulu ekujoliswe kulo, ngoko ke umphandi ifumana nemazi kunyaka-25 ubudala ukusuka lenjongo elimdaka ukuba kwisampulu etelekiswe. Okokugqibela, amalungu isampuli etelekiswe indlebe ukuvelisa iseti lokugqibela abaphenduli.
Nangona isampuli etelekiswe elijongeka isampulu ekujoliswe, kubalulekile ukukhumbula ukuba isampuli etelekiswe na isampuli ezinokwenzeka. iisampulu etelekiswe enazo kuphela isampulu ekujoliswe kwi ulwazi abangabancedani eyaziwa (umzekelo, ubudala, isini), kodwa hayi ngeempawu sigqithise. Ngokomzekelo, xa abantu kwiqela lenjongo mdaka badla wanzonza-emva zonke, esinye isizathu ukuba bazibandakanye iphaneli saveyi imali-ngoko nkqu nokuba isampuli etelekiswe elijongeka sample ekujoliswe ngokwemiqathango ubudala ngesondo kuya kuqhubeka lutyekele kubantu abangamahlwempu. Kummangaliso okwenyaniso ezinokwenzeka isampulu kulawula iingxaki omabini iimpawu kulinganiswa kwaye sigqithise (ingongoma engqinelana ingxoxo yethu kuthelekiseka ngokuba ithethe woko ukusuka kwizifundo lokuqwalasela kwiSahluko 2).
Ukuziqhelisa, ethelekisa isampulu kuxhomekeke kwiphaneli elikhulu ezahlukeneyo wayelangazelela ukugqiba uphando, ngoko kakhulu kwenziwa ziinkampani abanako ukuhlawula ukuphuhlisa nokugcina yolawulo enjalo. Kwakhona, ngokomsebenzi, kuba kukho iingxaki matching (ngamanye amaxesha umdlalo elungileyo umntu kwisampulu ekujoliswe akasekho lenjongo) kwaye non-impendulo (ngamanye amaxesha abantu isampuli etelekiswe ukwala inxaxheba kwisaveyi). Ngoko ke, xa kusenziwa, abaphandi ukwenza ethelekisa isampulu kwakhona enze ezinye uhlobo ulungelelwaniso post-abahlulwe ukwenza uqikelelo.
Kunzima ukunika ingqinisekiso luncedo ithiyori malunga ethelekisa isampulu, kodwa ukwenza oko ukwenza kakuhle. Ngokomzekelo, uStefano Ansolabehere no Brian Schaffner (2014) xa kuthelekiswa uphando ezintathu engumzekelo abantu 1,000 kuqhutywa ngo-2010 usebenzisa isampulu ezintathu ezahlukeneyo udliwano iindlela: mail, ngefowuni, kwaye yiphaneli Internet usebenzisa ethelekisa lwesampulu kunye nokulungelelanisa post-abahlulwe. Uqikelelo ukusuka iindlela ezintathu zazifana kakhulu ukuba uqikelelo ukusuka labeka ophezulu ezikumgangatho ezifana Current Population Survey (CPS) kunye yezeMpilo yeSizwe Udliwano Survey (NHIS). Ngokungakumbi, zombini iisaveyi Internet kunye neposi aqhuzulwa ngomyinge we-3 pesenti ngamanqaku kwaye uphando yayiyile off 4 ipesenti ngamanqaku. Iimpazamo ezinkulu kulo malunga into enye ubunokukulindela iisampuli abantu abamalunga nama-1,000. Nangona, akukho nanye yezi iindlela eziveliswa data kakhulu ngcono, zombini uphando Internet yefowuni (apho iintsuku okanye iiveki) baba kakhulu oluikhawuleza entsimini ngaphezu phando ngeposi (leyo yathabatha iinyanga ezisibhozo), yaye uhlolisiso Internet, apho kusetyenziswa ethelekisa isampulu, iindleko kunezinye iindlela ezimbini.
Elokuphetha, oosonzululwazi zentlalo manani zintsonkothe yoku- nokuthelekelela kwezi iisampuli non-ngokuqinisekileyo, ngokuyinxenye ngenxa yokuba zinxulunyaniswa iintsilelo iintloni uphando uphando ezifana yokuFunda Digest nokuvota. Ngokuyinxenye, ndivumelana kukulumka: iisampuli non-linokuba unadjusted kusenokwenzeka ukuvelisa uqikelelo ezimbi. Kodwa ke, ukuba abaphandi Unga nyenyisa ngenxa yocalu kwinkqubo isampulu (umzekelo, iposi-abahlulwe) okanye ukulawula inkqubo isampulu ngandlel '(umzekelo, isampulu ukutshatisa izinto), bakwazi ukuvelisa uqikelelo ngcono, nkqu luqikelela olusemgangathweni ngeenjongo ezininzi. Kakade ke, kuya kuba ngcono ukuba babulawe ngokugqibeleleyo linokuba isampulu, kodwa ukuba akukho kuphinda kubonakala ukuba kuko.
Zombini non-linokuba kunye neesampuli linokuba ziyahluka kumgangatho wabo, kwaye ngoku kungenzeka kwimeko ukuba iingqikelelo ukusuka iisampuli linokuba kakhulu athembeke ngaphezu uqikelelo ukusuka iisampuli non-ezinokwenzeka. Kodwa ke, nangoku, uqikelelo ukusuka iisampulu non-linokuba kakuhle-kuqhutywa mhlawumbi ngaphezu uqikelelo ukusuka iisampulu linokuba kakubi-kuqhutywa. Ngaphezu koko, iisampulu non-linokuba olufana zitshiphu. Ngoko ke, kuyabonakala ukuba amathuba vs non-linokuba isampulu inika ngexabiso-esemgangathweni yorhwebo-off (Figure 3.6). Ndikhangela phambili, ndiya silindele ukuba uqikelelo ukusuka iisampuli non-linokuba kakuhle-enze kuya kuba lula yaye kuxabise ngcono. Ngokubhekele phaya, ngenxa yokuwa kuphando umnxeba wocingo kunye nokwandisa amazinga non-impendulo, ndiya silindele ukuba iisampulu linokuba eya kuba ziindleko ezinkulu kakhulu kunye nomgangatho ophantsi. Ngenxa yezi osele unexesha elide, ndicinga ukuba non-linokuba isampulu uya kuba kakhulu kwiindawo localu wesithathu uphando uphando.
Isazobe 3.6: Ingqikelelo isampuli xa efundisa non-linokuba isampulu zinkulu zombini iindidi, ngeentlobo. Ngokubanzi, kukho impazamo iindleko-kurhwebo-off ne non-linokuba isampulu abe nexabiso kodwa impazamo ephakamileyo. Nangona kunjalo, kakuhle-enze non-linokuba isampulu inokuvelisa uqikelelo ngaphezu kakubi-kwenziwe izinto ezinokwenzeka isampulu. Kwixa elizayo, ndiya silindele ukuba non-linokuba isampulu kuya kuba bhetele kwaye kungabizi xa linokuba isampulu kuya mandundu ezibizayo.
