3.4 Ngubani ukubuza
Iisampulu Okungathi kunye neesampuli non-linokuba azahlukanga ukuba ndlela; kuzo zombini ezi meko, oko konke malunga amatye.
Isampulu sisisekelo kulibhala uphando. phantse Abaphandi kuze ukubuza imibuzo yabo bonke abemi lwabo. Kulo mba, iisaveyi akuwedwa. zophando ezininzi, ngendlela enye okanye omnye, kubandakanya isampulu. Ngamanye amaxesha sampling kwenziwa awuyenzi ngumphandilo; Ngamanye amaxesha kuyenzeka ngokupheleleyo. Ngokomzekelo, umphandi ukuba uqhuba lamava elabhoratri abafundi zesidanga eyunivesithi wakhe uye wathabatha isampula. Ngoko, isampulu yingxaki esiphuma kuyo le ncwadi. Enyanisweni, omnye iinkxalabo zixhaphakileyo ndiyivayo imithombo ubudala yedijithali lwedatha "abekho ummeli." Njengoko siza kubona kweli Candelo, le nkxalabo zombini nabungozi yaye inobuqhophololo ngaphezu ntu abaninzi beqaphela. Enyanisweni, ndiya kuxoxa ukuba yonke ingqikelelo "ukumelwa" akukho luncedo kuba ecinga iisampulu linokuba and non-ezinokwenzeka. Endaweni yoko, isitshixo ukuba ucinge ndawonye njani idata kunye nendlela kususwa naziphi ucalu kuloo ukuqokelelwa kwedatha xa ukwenza uqikelelo.
Okwangoku, indlela lubalaseleyo theoretical ukuba umelo ezinokwenzeka isampulu. Xa data ziqokelelwa kunye mhlawumbi indlela yeesampulu eye singaphunyezwa ngokugqibeleleyo, abaphandi bakwazi ukukhulisa ubunzima data babo ngokusekelwe kwindlela ukuba Baqokelelana ukwenza uqikelelo cala malunga ekujoliswe kubo. Nangona kunjalo, egqibeleleyo wokuqashisela isampulu iindidi yenzeke ehlabathini lokwenene. Kukho ngokokuqhelekileyo ziingxaki ezimbini eziphambili 1) umahluko phakathi ekujoliswe kubo yaye abemi isakhelo 2) non-impendulo (ezi kanye iingxaki zaphuka yokuFunda Digest nokuvota). Ngoko ke, kunokuba ucinga ezinokwenzeka isampuli njengoko ungumzekelo ocacileyo yintoni ngokwenene eyenzekayo ehlabathini, kungcono ukuba bacinge ezinokwenzeka isampuli njengoko luncedo, umzekelo nje, efana kakhulu zamachiza indlela cinga ibhola ukungavani ukuqengqeleka ubude lee ethambekeni.
Uhambelwano ezinokwenzeka ukukhiwa non-ezinokwenzeka isampulu. Umahluko ophambili phakathi ezinokwenzeka and non-linokuba ukukhiwa ukuba ezinokwenzeka iisampula wonke abemi kunethuba eyaziwa ukufakwa. Kukho, enyanisweni, iintlobo ezininzi non-ezinokwenzeka isampulu, kwaye ezi ndlela yokuqokelelwa kwedatha kuya kusanda eqhelekileyo kweminyaka yesuntswana. Kodwa, non-amathuba isampulu owaziwa eyoyikekayo phakathi ntle kunye manani. Enyanisweni, non-wokuqashisela isampulu linxulunyaniswa ezinye yokusilela okona kutyhilwa labaphandi uphando, ezifana yokuFunda Digest fiasco (kuxoxwa ngaphambili) kunye nakweli tyeli malunga US konyulo ngumongameli 1948 ( "Dewey koyiswa Truman") (Mosteller 1949; Bean 1950; Freedman, Pisani, and Purves 2007) .
Noko ke, ixesha ilungelo ngokutsha non-linokuba isampuli ngenxa yezizathu ezibini. Okokuqala, njengokuba iisampulu wokuqashisela lube nzima ukuyenza umsebenzi, umgca phakathi iisampulu linokuba kunye neesampuli non-linokuba yi awusiso. Xa kukho amazinga aphezulu non-impendulo (njengoko kukho kuphando ngokwenene ngoku), amathuba kanye inclusions ngenxa abaphenduli hayi ezaziwa, yaye ngaloo ndlela, iisampulu amathuba kunye neesampuli non-linokuba azikho ezahlukileyo abaphandi abaninzi bakholelwa. Enyanisweni, njengoko siza kubona ngezantsi, lithetha zombini iindlela bathembele kuchazo Indlela yokulinganisela: post-abahlulwe. Okwesibini, ukuba uphuhliso ezininzi ekuqokelelweni ucalulo lwemizekelo non-ezinokwenzeka apho. Ezi ndlela zahluke ngokwaneleyo ukusuka iindlela ibangele iingxaki ngaphambili endicinga ukuba iyavakala ukucinga ngabo "non-ezinokwenzeka isampulu 2.0." Sifanele ukuba nentiyo ezingenangqondo iindlela non-amathuba ngenxa yeziphoso eyenzeke kudala dala kakhulu.
Okulandelayo, ukuze wenze le ngxoxo eziphathekayo kakhulu, ndiza kwakhona isampuli okwenzeka umgangatho weighting (Icandelo 3.4.1). Ingcamango isitshixo enazithabathayo ukuba indlela data yakho kufuneka nefuthe wenze njani uqikelelo. Ngokukodwa, ukuba wonke umntu akanaye linokuba efanayo yokubandakanywa, ngoko wonke kufanele ukuba ubunzima efanayo. Ngamanye amazwi, ukuba isampuli lakho yedemokhrasi, ngoko uqikelelo lwakho kuba yedemokhrasi. Emva kokuhlolisisa weighting, ndiza uchaze iindlela ezimbini ezingezo-linokuba isampulu: ngulowo ugxininisa weighting ukujongana nengxaki ye data ngokungalungelelananga eziqokelelweyo (Section 3.4.2), kwaye umntu uzama ukubeka ulawulo phezu ngayo ezi nkcukacha eziqokelelweyo (Section 3.4.3). Iingxoxo kwisicatshulwa eziphambili ziya kucaciswa ngezantsi amagama kunye nemifanekiso; readers oyakuthanda unyango zemathematika engakumbi kufuneka nayo funda isihlomelo zobugcisa.
