Isikhathi sokuqiniseka. Iyini futhi ingasetshenziswa kanjani?

Isikhathi sokuqiniseka sifike kithi ensimini yezibalo. Lena ibanga elithile, elisebenzela ukuhlola ipharamitha engaziwa ngezinga eliphezulu lokuthembeka. Indlela elula yokuchaza lokhu iyisibonelo.

Ake sithi ufuna ukuphenya inani elithile elingavamile, isibonelo, isivinini sempendulo yesiphakeli kwesicelo siklayenti. Njalo uma umsebenzisi edayela ikheli lendawo ethile, iseva iphendula ngalokhu ngezinga elihlukile. Ngakho, isikhathi sokuphendula ngaphansi kokucwaninga sihleliwe. Ngakho, isikhathi sokuzethemba sisenza sikwazi ukucacisa imingcele yalesi parameter, bese kuzokwenzeka ukuthi kungenzeka ngamaphesenti angama-95% isivinini sokuphendula seseva sizoba ebangeni esibalalayo.

Noma udinga ukuthola ukuthi bangaki abantu abakwaziyo mayelana nenkampani yenkampani. Uma isikhathi sokubheka sibalwa, kuzokwenzeka, isibonelo, ukusho ukuthi nge-95% isabelo samathuba, isabelo sabathengi abazi ngalolu mkhiqizo sisukela ku-27% kuya ku-34%.

Leli gama lihlobene eduze nalokho okubaluleka njengokungathi ukuzethemba. Kungenzeka ukuthi ipharamitha elifunayo lingena esikhathini sokuzethemba. Kule nzuzo kuxhomeke ukuthi ububanzi bethu obufunayo buzoba bunjani. Ukubaluleka okubaluleke kakhulu, isikhathi sokuzethemba sibe ngaphezulu, futhi ngokufanayo. Ngokuvamile isethwe ku 90%, 95% noma 99%. Inani lama-95% lithandwa kakhulu.

Lesi sibonakaliso siphinde sithonywe ukuhluka kokubheka kanye nobukhulu besampula. Incazelo yalo isekelwe ekucatshangweni ukuthi isici esiphenywe sithobela umthetho wokusabalalisa ovamile. Lesi sitatimende saziwa nangokuthi uMthetho weGaussian. Ngokusho kwakhe, ukusatshalaliswa kwazo zonke izimo eziguquguqukayo zokuguquguquka okungahleliwe kubizwa ngokuthi okujwayelekile, okungahlathululelwa ngobuningi bokuba namandla. Uma ukucabanga kokusatshalaliswa okujwayelekile kuye kwaba iphutha, ukulinganisa kungenzeka ukuthi akulungile.

Okokuqala, ake sibheke indlela yokubala isikhawu sokuzethemba sokulindela izibalo. Lapha kukhona amacala amabili. Ukuhluka (izinga lokuhluka kwehlukahluka okungahleliwe) kungaziwa noma cha. Uma kwaziwa, isikhathi sethu sokuzethemba sibalwa ngokusebenzisa ifomula elandelayo:

I-Xsr - t * σ / (sqrt (n)) <= α <= xcp + t * σ / (sqrt (n)), kuphi

Α kuyinto uphawu,

T ipharamitha kusuka etafuleni lokusabalalisa laseLaplace,

I-Sqrt (n) ingumsuka wesigcawu usayizi wesampula esiphelele,

Σ yisisekelo sendawo yokuhluka.

Uma ukungafani kungaziwa, khona-ke kungabalwa uma sazi zonke izindinganiso zesici esifunayo. Ukuze wenze lokhu, sebenzisa ifomula elandelayo:

Σ2 = x2cp - (xcp) 2, kuphi

I-X2cp yinani elilinganiselwe lezikwele zesici sokuhlola,

(I-Xcp) 2 yikwele yenani elibalulekile lalesi sici.

Ifomula yokubala isikhathi sokuzethemba kulokhu kuhluka kancane:

I-Xsp - t * s / (sqrt (n)) <= α <= xcp + t * s / (sqrt (n)), kuphi

Хср - isilinganiso esinqunyiwe,

Α kuyinto uphawu,

I-parameter etholakala ngokusebenzisa ithebula lokusabalalisa lomfundi t = t (ɣ; n-1),

I-Sqrt (n) ingumsuka wesigcawu usayizi wesampula esiphelele,

S yizimpande zendawo yokuhluka.

Cabanga ngalesi sibonelo. Ake sithi ngokusekelwe emiphumela yezilinganiso ezingu-7, inani elilinganiselwe lesici sokuhlola linqunywe elilingana no-30 nokuhluka kwesampula okulingana no-36. Kubalulekile ukuthola ngamathuba angu-99% isikhathi sokuzethemba esinexabiso langempela lepharamitha elilinganisiwe.

Okokuqala, sichaza okulingana no: t = t (0.99, 7-1) = 3.71. Sisebenzisa ifomu elingenhla, sithola:

I-Xsr - t * s / (sqrt (n)) <= α <= xcp + t * s / (sqrt (n))

30 - 3.71 * 36 / (sqrt (7)) <= α <= 30 + 3.71 * 36 / (sqrt (7))

21.587 <= α <= 38.413

Isikhathi sokuzethemba sokuhlukahluka sibalwa kokubili esimweni sokwaziswa okuyaziwayo, futhi uma kungekho idatha ekulindeni kwesibalo, futhi kuphela inani lephuzu elilinganiselwe lokulinganisa okungaqondakali. Ngeke sinikeze lapha amafomu okubalwa kwawo, ngoba kunzima kakhulu futhi, uma befisa, bangatholakala njalo kunetha.

Siyazi ukuthi kulula ukucacisa isikhathi sokuzethemba usebenzisa uhlelo lwe-Excel noma isevisi yenethiwekhi, okuthiwa yiyo.