Mann-Whitney xeem: ib qho piv txwv rooj

Kauj nyob rau hauv lej statistics - ib tug nruj txoj cai, nyob rau hauv raws li cov kev xav uas ib tug tej theem ntawm tseem ceeb yog txais los yog tsis lees txais. Yuav kom tsim nws, koj yuav tsum nrhiav ib txog kev ua. Nws yuav tsum nyob ntawm seb qhov kawg kev tshwm sim ntawm qhov xyaum ua tej, uas yog, los ntawm lub empirically determined qhov tseem ceeb. Nws yog qhov no feature yuav tsum muaj ib tug cuab tam rau kev ntsuam xyuas qhov sib txawv ntawm qhov kev kuaj.

Cov lus tseem ceeb muaj nuj nqis. Txheej txheem cej luam

Statistical tseem ceeb - yog tus nqi ntawm qhov yuav tshwm ntawm lub caij nyoog tshwm sim yog tsawg heev. Tsis tseem ceeb txaus raws li ntau heev thiab nws ua tau zoo. Qhov txawv yog hu ua cov lus tseem ceeb nyob rau hauv lub rooj plaub uas muaj cov ntaub ntawv, qhov yuav tshwm ntawm uas yog negligible yog hais tias tus hais tias cov kev txawv no tsis muaj nyob. Tab sis qhov no tsis txhais hais tias qhov no sib txawv yuav tsum tau yuav loj thiab tseem ceeb.

Cov theem ntawm statistical tseem ceeb xeem

Qhov no lub sij hawm yuav tsum tau to taub yuav tsis kam lees yuav lub thov hypothesis nyob rau hauv cov ntaub ntawv ntawm nws qhov tseeb. Qhov no tseem hu ua ib qho yuam kev ntawm cov thawj zoo, los yog cuav zoo kev txiav txim siab. Nyob rau hauv feem ntau tus neeg mob, tus txheej txheem yog raws li nyob rau hauv p-nqi ( "pi-nqi"). Qhov no cumulative probability los tsom kwm rau cov theem ntawm statistical xeem. Nws, nyob rau hauv lem, muaj ib tug qauv thaum lub sij hawm ntawm tus me nyuam ntawm cov thov hypothesis. Lub suggestion yuav yuav tsis lees txais yog hais tias tus p-nqi yog tsawg tshaj li tus tshaj tawm hais tias theem analyst. Los ntawm no daim duab nyob ncaj qha tseem ceeb xeem qhov tseem ceeb: tus me nws yog, lub, ntsig txog, thiab ntau vim li cas yuav tsis tau txais cov kev xav. Qhov tseem ceeb theem no feem ntau yog denoted los ntawm tsab ntawv B (alpha). Nrov nuj nqis ntawm cov kws tshwj xeeb: 0.1%, 1%, 5% thiab 10%. Yog hais tias, piv txwv li, hais tias qhov uas yuav muaj ib tug match yog 1 nyob rau hauv 1000, ces nws yeej yog peb sib tham txog lub 0.1% theem ntawm statistical tseem ceeb ntawm ib tug random nce mus nce los. Txawv lub ntsiab b-theem muaj lawv tus kheej pros thiab cons. Yog hais tias lub Performance index yog tsawg ces tus loj dua cov ntxim yuav zoo siv uas lwm hypothesis yog tseem ceeb. Txawm tias qhov no yuav yog ib tug uas muaj feem yuav hais tias ib tug cuav thov hypothesis yog tsis tso tseg. Nws muaj peev xwm yuav xaus lus tias cov kev xaiv ntawm cov pom b-theem nyob rau qhov nqi koj tshuav ntawm "qhov tseem ceeb ntawm lub hwj chim" los yog, ntsig txog, ntawm cov dabtsi tshwm sim rau ib tug cuav zoo thiab cuav tsis zoo kev txiav txim siab. Synonymous nrog "statistical tseem ceeb" nyob rau hauv Lavxias teb sab ntaub ntawv yog lub sij hawm "authenticity".

Kev txiav txim ntawm lub thov hypothesis

Nyob rau hauv lej statistics, qhov no assumption yog soj ntsuam txog kev taub hau nrog uas twb muaj lawm empirical pov thawj nyob rau hauv tes. Nyob rau hauv Feem ntau, lub thov hypothesis yog coj hypothesis hais tias ib tug correlation ntawm txoj kev tshawb no ntau yam yog uas ploj lawm los yog hais tias tsis tas yuav kawm rau hauv lub tsev uniformity sib txawv. Nyob rau hauv tus txheej txheem tshawb fawb mathematician sim tsis pom zoo rau cov thov hypothesis, uas yog, los ua pov thawj hais tias nws yog tsis muaj raws li cov kev sim tshawb pom. Thiab mus rau qhov chaw thiab ib tug lwm txoj hypothesis uas yog txais es tsis txhob ntawm ib tug pes tsawg.

lus txhais tseem ceeb

Kauj U (Mann-Whitney) nyob rau hauv lej statistics tso cai los soj ntsuam qhov sib txawv nruab nrab ntawm ob kuaj. Lawv yuav tsum tau muab nyob rau theem ntawm ib tug kev zoo losis phem uas yog ntsuas quantitatively. Qhov no txoj kev yog zoo tagnrho rau cov kev luj xyuas ntawm qhov sib txawv ntawm me me. Qhov no yooj yim txog kev paub twb npaj siab los ntawm Frank Wilcoxon nyob rau hauv 1945. Thiab twb nyob rau hauv 1947, txoj kev tau kho thiab ntxiv los zaum H. B. Mann thiab D. R. Uitni, cov npe ntawm uas nws raug hu los hnub no. Mann-Whitney xeem nyob rau hauv psychology, lej, statistics, thiab ntau lwm yam sciences yog ib tug ntawm cov yuav tsum muaj cov ntsiab ntawm cov zauv hauv paus ntawm theoretical kev tshawb fawb.

piav qhia

Mann-Whitney - ib tug kuj yooj yim txoj kev tsis tsis. Nws muaj peev xwm yog tseem ceeb. Nws yog ho siab tshaj lub hwj chim Rosenbaum Q-xeem. Cov kev xeem yuav ua li cas me me lub cheeb tsam ntawm tus ntoo khaub lig-qhov tseem ceeb ntawm qhov kev kuaj, namely ntawm lub kab ntawm lub ranked qhov tseem ceeb ntawm cov thawj thiab thib ob xaiv. Tus nqi yog tsawg tshaj li tus qauv tshau, qhov ntau dua hais tias cov parameter qhov tseem ceeb yog siv tau txawv. Yuav kom zoo thov lub kauj U (Mann-Whitney), tsis txhob hnov qab txog tej kev txwv. Txhua qauv yuav tsum muaj tsawg kawg yog 3 yam ntxwv nqi. Nws yog tau hais tias nyob rau hauv ib tug cov ntaub ntawv tseem ceeb ntawm cov ob tug, tab sis lub thib ob lub sij hawm lawv tau yuav tsum yog tsawg kawg yog tsib. Nyob rau hauv lub xeem kuaj yuav tsum yog qhov tsawg kawg nkaus naj npawb ntawm cov coincident ntsuas. Tag nrho cov zauv yuav tsum tau txawv nyob rau hauv qhov zoo tshaj plaws cov ntaub ntawv.

kev siv cov

Yuav ua li cas kom siv cov Mann-Whitney kev kuaj no? Rooj, uas yog tsim los ntawm cov qauv no muaj ib tug tej yam tseem ceeb heev tus nqi. Ua ntej koj yuav los ua ib tug tib set ntawm ob matched kuaj, uas yog ces ranked. Uas yog, lub ntsiab yog cov txheej txheem ntawm raws li cov neeg kawm ntawv ntawm kev nce ntawm feature thiab qis nyob qib yog muab rau tus me nqi. Raws li ib tug tshwm sim, peb tau tag nrho cov xov tooj ntawm cov kawm qib:

N = N1 + N2,

qhov twg rau qhov tseem ceeb N1 thiab N2 - cov chav nyob muaj nyob rau hauv tus thawj thiab thib ob kuaj feem. Ntxiv mus, ib tug tib ranked tooj tseem ceeb yog muab faib ua ob pawg. Chav, ntsig txog, tus thawj thiab thib ob kuaj. Tam sim no suav nyob rau hauv tig lub sum ntawm ibyam ntawm qhov tseem ceeb nyob rau hauv thawj thiab thib ob kab. Nws txiav txim feem ntau ntawm lawv (Tx), uas sib raug rau ib cov qauv nrog NX units. Yuav kom siv ntau Wilcoxon txoj kev, nws cov nqi yog xam los ntawm cov nram qab no txoj kev. Nws yog tsim nyog rau lub rooj los mus txiav txim xaiv theem ntawm tseem ceeb ntawm cov tseem ceeb heev txog kev paub rau lawv noj N1 thiab N2. Cov uas ua tivthaiv yuav ua tau tsawg dua los sis sib npaug zos rau cov nqi los ntawm lub rooj. Nyob rau hauv cov ntaub ntawv no, ib tug tseem ceeb sib txawv yog los nrog nkawd tham kev zoo losis phem ntau nyob rau hauv lub kawm qauv. Yog hais tias lub resulting tus nqi yog siab tshaj lub rooj, ces tus thov hypothesis yog txais. Thaum lub xam yog ua Mann-Whitney xeem, nws yuav tsum tau muab sau tseg tias yog hais tias lub thov hypothesis yog muaj tseeb, lub kauj yuav tau lub expectation, raws li zoo raws li dispersion. Nco ntsoov hais tias rau loj tagnrho ntawm cov ntaub ntawv kuaj txoj kev yog suav tias yog yuav luag ib txwm muab faib rau. Qhov tseem ceeb ntawm txawv yog ntau dua, tus nqi yuav tsawg heev Mann-Whitney xeem.