Uluqonda njani ixesha lokuzithemba kwinani labemi

Ngu-Deborah J. Rumsey

Ungayifumana ifayile ye- Ixesha lokuzithemba (CI) kwinani labemi ukubonisa ubalo olunokwenzeka lokuba uphawu lunokwenzeka ukuba lubekho kubemi.



Xa umlinganiso olinganisiweyo ulwahlulo-umzekelo, uluvo kumcimbi (ukuxhasa, ukuchasa, okanye ukungathathi cala), isini, iqela lezopolitiko, okanye uhlobo lokuziphatha (musa / unganxibi ibhanti xa uqhuba) - uninzi lwabantu lufuna ukuqikelela inani (okanye ipesenti) labantu kubemi abawela kudidi oluthile lomdla. Umzekelo, cinga ipesenti yabantu abaxhasa iveki ezine zomsebenzi weveki, ipesenti yabantu baseRiphabhlikhi abavote kunyulo oludlulileyo, okanye inani labaqhubi abangawafakanga amabhanti ezihlalo. Kwimeko nganye kwezi, into kukuqikelela inani labemi, p, usebenzisa isampulu yenxalenye,

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dibanisa okanye thabatha umda wempazamo. Iziphumo zibizwa ngokuba yi ithuba lokuzithemba kwinani labemi, iphe.



Ifomula ye-CI yenani labemi yile

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yinxalenye yesampulu, n bubungakanani besampulu, kunye nge * lixabiso elifanelekileyo ukusuka kulwabiwo oluqhelekileyo oluqhelekileyo kwinqanaba lakho lokuzithemba. Olu luhlu lulandelayo lubonisa amaxabiso nge * kumanqanaba athile okuzithemba.



nge * - Ixabiso leMigangatho eyahlukeneyo yokuThembela
Inqanaba lokuzithemba z * -ixabiso
80% 1.28
90% 1.645 (ngendibano)
95% 1.96
Iipesenti ezingama-98 2.33
99% 2.58

Ukubala i-CI ngenani labemi:

  1. Chonga inqanaba lokuzithemba kwaye ufumane okufanelekileyo nge * -xabiso.

    Jonga kule theyibhile ingentla nge * -ixabiso.

  2. Fumana isampula,

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    ngokwahlula inani labantu kwisampulu enophawu lomdla kubungakanani besampulu ( n ).

    Phawula: Esi siphumo kufuneka sibe lixabiso ledesimali phakathi kwe-0 kunye ne-1.

  3. Yandisa

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    uze wahlule eso sixa nge n.

  4. Thatha ingcambu yesiphumo kwiNqanaba 3.

  5. Yandisa impendulo yakho ngo nge * .

    Eli nyathelo likunika umda wempazamo.

  6. Thatha

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    yi-zetia umthetho

    dibanisa okanye thabatha umda wempazamo ukufumana i-CI; isiphelo esezantsi se-CI ngu

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    thabatha umda wempazamo, kwaye isiphelo esiphezulu se-CI ngu

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    kunye nomda wempazamo.

Ifomula eboniswe kumzekelo ongentla we-CI iphe isetyenziswa phantsi kwemeko yokuba ubungakanani besampulu bukhulu ngokwaneleyo ukuba isetyenziswe kwi-Central Limit Theorem kwaye ikuvumele usebenzise i nge -Ixabiso, elenzeka kwimeko apho uqikelela ubungakanani ngokusekwe kuphando olukhulu. Kwiisampulu ezincinci zobungakanani, ixesha lokuzithemba kwinxalenye zihlala zingaphaya komgangatho wesifundo sezibalo.

Umzekelo, cinga ukuba ufuna ukuqikelela ipesenti yexesha (nge-95% yokuzithemba) kulindeleke ukuba ufumane isibane esibomvu kwimpambano ethile. Masithi uthatha isampulu engahleliwe yeehambo ezili-100 ezahlukeneyo ngale ndlela yokuhlangana kwaye ufumanisa ukuba isibane esibomvu sabethwa amatyeli angama-53.

  1. Kuba ufuna i-95% yexesha lokuzithemba, lakho nge * Ixabiso li-1.96.

  2. Isibane esibomvu sabetha ama-53 kwali-100 amaxesha. Ke

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  3. Khangela

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  4. Thatha ingcambu yesikwere ukufumana i-0.0499.

    Umda wempazamo, ngoko ke, dibanisa okanye thabatha u-1.96 ∗ 0.0499 = 0.0978, okanye 9.78%.

  5. Ixesha lakho lokuzithemba elingama-95% kwipesenti yamaxesha oya kuthi ubethe ngawo ukukhanya kwelo khonkco lingu-0.53 (okanye ama-53%), kunye kunye okanye thabatha u-0.0978 (ujikeleziselwe ku-0.10 okanye kwi-10%). (Isiphelo esisezantsi sekhefu ngu-0.53 - 0.10 = 0.43 okanye i-43%; isiphelo esingaphezulu ngu-0.53 + 0.10 = 0.63 okanye i-63%.)

    Ukutolika ezi ziphumo ngokwemeko yengxaki, ungatsho ukuba nge-95% yokuzithemba ipesenti yamaxesha onokulindela ukubetha ngokukhanya kolu hlangothi liphakathi kwe-43% kunye ne-63%, ngokusekwe kwisampulu yakho.