Iyini i-Null kanye ne-Alternative Hypothesis?
Ezindleleni zezibalo kanye nocwaningo, amagama athi null hypothesis (H0) kanye ne-alternative hypothesis (H1 noma Ha) yimibono emibili eyisisekelo evame ukuvela lapho abacwaningi befuna ukuhlola i-hypothesis besebenzisa idatha. Bakha isisekelo sokuhlolwa kwe-hypothesis, inqubo yokunquma ukuthi ubufakazi obuvela kusampula bunamandla ngokwanele yini ukusekela isimangalo mayelana nenani labantu. Nakuba kungase kuzwakale njengobuchwepheshe, umqondo oyisisekelo empeleni ulula: senza izitatimende ezimbili eziphikisanayo, bese sisebenzisa idatha ukunquma ukuthi iyiphi enengqondo kakhulu.
Ukuqonda i-hypothesis ocwaningweni
Ngokuvamile, i-hypothesis iwukucabanga noma isitatimende esingahlolwa ukuthi siyiqiniso yini. Ocwaningweni lwezibalo, i-hypotheses ivame ukwakheka ngesimo sobudlelwano phakathi kwezinto eziguquguqukayo noma umehluko phakathi kwamaqembu. Isibonelo: "Indlela yokufunda u-A isebenza kangcono kunendlela yokufunda u-B" noma "Kukhona ubudlelwano phakathi kwesikhathi sokulala kanye namazinga okuhlushwa."
Kodwa-ke, uma lezi zincazelo zilethwa emkhakheni wokuhlaziywa kwezibalo, zivame ukuhlukaniswa zibe yizibili: i-null hypothesis kanye ne-alternative hypothesis.
Iyini i-null hypothesis (H0)?
I-null hypothesis (H0) iyisitatimende esivame ukuthi akukho mehluko, akukho mphumela, noma akukho buhlobo. I-H0 ivame ukubhekwa njengesikhundla "esizenzakalelayo" noma "sesimo esikhona". Ezivivinyweni zezibalo, abacwaningi bavame ukuqala ngomcabango wokuthi i-H0 iyiqiniso bese befuna ubufakazi obuvela kudatha ukuze benqabe.
Izici ezijwayelekile ze-null hypothesis:
1. Ukusho ukuthi akukho mphumela noma akukho mehluko.
2. Yiba yisikhombisi sokuqala ekuhlolweni.
3. Kwenqatshwa noma kwehlulekile ukwenqatshwa ngokusekelwe emiphumeleni yokuhlolwa kwezibalo.
Isibonelo se-null hypothesis:
– “Akukho mehluko emabangeni aphakathi phakathi kwamakilasi asebenzisa indlela A kanye nendlela B.”
– “Akukho ubudlelwano phakathi kwenani lamahora okufunda kanye namamaki ezivivinyo.”
– “Ukuphakama okujwayelekile kwabafundi kungu-165 cm.”
Ku-notation yezibalo, i-null hypothesis ivame ukuhilela uphawu lwe-=, isibonelo μ = 165 noma p = 0,5. Uphawu olulinganayo lubalulekile ngoba i-H0 ivame ukuthi ipharamitha yenani labantu isezingeni elithile.
Iyini i-alternative hypothesis (H1/Ha)?
I-alternative hypothesis (H1 noma Ha) iyisitatimende esiphikisana ne-null hypothesis. I-H1 ithi kukhona umehluko, umphumela, noma ubudlelwano. Uma i-H0 yenqatshwa, umcwaningi uthola ukwesekwa kwe-H1 (nakuba ngokobuchwepheshe, lokhu ukwenqaba i-H0, hhayi "ukufakazela" i-H1 ngokuphelele).
Izici ezijwayelekile zemibono ehlukile:
1. Ukusho ukuthi kukhona umphumela, umehluko, noma ubudlelwano.
2. Yiba umgomo oyinhloko abacwaningi abafuna ukuwusekela.
3. Kwamukelwa ngokungaqondile lapho i-H0 yenqatshwa.
Izibonelo zemibono ehlukile:
– “Kukhona umehluko enanini elimaphakathi phakathi kwendlela yekilasi A nendlela B.”
– “Kukhona ubudlelwano phakathi kwenani lamahora okufunda kanye namamaki ezivivinyo.”
– “Ukuphakama okujwayelekile kwabafundi akulingani no-165 cm.”
Ekubhalweni, i-H1 ivame ukusebenzisa uphawu ≠, >, noma < kuye ngohlobo lokuhlolwa. Ubudlelwano phakathi kwe-H0 ne-H1: izitatimende ezimbili ezingahambisani. I-H0 ne-H1 kumele zihlukane, okusho ukuthi azinakuba yiqiniso ngesikhathi esisodwa. Uma i-H0 ithi “akukho mehluko,” khona-ke i-H1 ithi “kukhona umehluko.” Lokhu kubhanqa kwenziwa ngamabomu ukuze abacwaningi bakwazi ukwenza izinqumo ezicacile ngokusekelwe kudatha. Isibonelo, uma ucwaningo lufuna ukuthola ukuthi umuthi omusha uyawehlisa yini umfutho wegazi: - H0: Umuthi omusha awuwehlisi umfutho wegazi (noma ukwehla kufana nomuthi omdala). - H1: Umuthi omusha wehlisa umfutho wegazi (ngokuphumelela kakhudlwana). Ngedatha evela ekuhlolweni, abacwaningi benza izivivinyo zezibalo ukuze babone ukuthi ubufakazi bunamandla ngokwanele yini ukwenqaba i-H0. Izinhlobo zezinkolelo-mbono ezihlukile: ezinomsila owodwa kanye nezinomsila emibili
Ezinye izindlela zokucabangela zingaba yizinsila ezimbili noma umsila owodwa. 1. Ukuhlolwa kwemisila emibili - I-H1 ithi "ihlukile" ngaphandle kokucacisa okukhulu noma okuncane. - Isibonelo: - H0: μ = 165 - H1: μ ≠ 165 Lokhu kuhlolwa kusetshenziswa uma umcwaningi efuna ukwazi kuphela ukuthi kukhona umehluko, ngaphandle kwesiqondiso esithile. 2. Ukuhlolwa kwemisila eyodwa - I-H1 isho isiqondiso somehluko: omkhulu noma omncane. - Isibonelo: - H0: μ ≤ 165 - H1: μ > 165noma
– H0: μ ≥ 165
– H1: μ < 165 Lokhu kuhlolwa kusetshenziswa uma umcwaningi esevele enombono oqondile osekelwe ku-theory noma ezifundweni zangaphambilini. Ukukhetha ukuhlolwa okunomsila owodwa noma emibili kubalulekile ngoba kuthinta indlela indawo yokwenqatshwa enqunywa ngayo kanye nokuchazwa kwemiphumela. Indlela yokwenza isinqumo: ukwenqaba noma ukwehluleka ukwenqaba i-H0 Ekuhlolweni kwe-hypothesis, izinqumo ezivamile yilezi: - Ukwenqaba i-H0: idatha inikeza ubufakazi obuqinile ngokwanele bokuthi imiphumela ayihambisani ne-H0. - Ukwenqaba i-H0: idatha ayinamandla ngokwanele ukwenqaba i-H0 (lokhu akusho ukuthi i-H0 ifakazelwe ukuthi iyiqiniso). Igama elithi "ukuhluleka ukwenqaba" lisetshenziswa ngoba ucwaningo olusekelwe kwisampula luhlala lunokungaqiniseki. Akuvamile "ukufakazela" okuthile ngokuqiniseka okuphelele; esingakwenza nje ukuhlola ukuthi ubufakazi obutholakalayo buqine kangakanani. Ithuluzi elilodwa elidumile lokwenza izinqumo yi-p-value: - Uma inani le-p < α (isibonelo, α = 0,05), khona-ke i-H0 yenqatshwa. - Uma inani le-p ≥ α, khona-ke i-H0 yenqatshwa. Nansi i-α yizinga lokubaluleka, umkhawulo wokubekezelelana komcwaningi mayelana nokwenzeka kokwenza iphutha lapho enqaba i-H0. Amaphutha ekuhlolweni kwe-hypothesis: Uhlobo I kanye nohlobo II Njengoba izinqumo zezibalo zingalungi ngaso sonke isikhathi, kunezinhlobo ezimbili zamaphutha aqashelwayo: 1. Iphutha lohlobo I (α) - Ukwenqaba i-H0 lapho i-H0 iyiqiniso. - Isibonelo: ukuphetha ngokuthi umuthi usebenza kahle uma ungasebenzi. 2. Iphutha Lohlobo II (β) - Ukwehluleka ukwenqaba i-H0 uma i-H0 ingamanga. - Isibonelo: ukuphetha ngomuthi akusebenzi uma empeleni usebenza kahle. Abacwaningi bavame ukulawula ingozi yephutha lohlobo I ngokusebenzisa i-α (isb., 0,05). Okwamanje, ingozi yephutha lohlobo II ihlobene namandla ocwaningo, usayizi wesampula, kanye nokuguquguquka kwedatha. Isibonelo esilula esivela empilweni yansuku zonke Cabanga ukuthi ufuna ukuhlola ukuthi ithimba lokukhiqiza liyathuthukisa yini ikhwalithi ngemva kokushintsha imishini. - H0: Ushintsho lomshini aluthuthukisi ikhwalithi ejwayelekile yomkhiqizo. - H1: Ushintsho lomshini luthuthukisa ikhwalithi ejwayelekile yomkhiqizo. Uqoqa idatha ngamaphutha okukhiqiza ngaphambi nangemva koshintsho lomshini. Uma imiphumela yokuhlaziya ikhombisa umehluko omkhulu (isb., amaphutha ayancipha kanye nenani le-p < 0,05), wenqaba i-H0 futhi usekela ukuthi umshini omusha usize. Isiphetho I-hypothesis engenalutho kanye ne-hypothesis ehlukile kuyinhliziyo yokuhlola i-hypothesis kuzibalo. I-hypothesis engenalutho (H0) ivame ukuthi akukho mphumela noma umehluko, kuyilapho i-hypothesis ehlukile (H1/Ha) ithi kukhona umphumela noma umehluko. Ngedatha, abacwaningi bahlola ukuthi ubufakazi bunamandla ngokwanele yini ukwenqaba i-H0. Ukuqonda lo mqondo kusisiza ukuthi sifunde imiphumela yocwaningo ngokuhlolisisa, siklame izivivinyo ezingcono, futhi senze izinqumo ezinengqondo nezisekelwe kudatha. Uma ungathanda, ngingakusiza ukuthi udale izibonelo zezinkolelo-mbono ezingafanele kanye nezihlukile ezihambisana nesihloko sakho socwaningo (isb., imfundo, impilo, ibhizinisi), eziphelele ngezivivinyo zezibalo ezifanele.
