General cov pej xeem thiab zauv

Txheej homogeneous khoom muaj feem ntau soj ntsuam nyob rau hauv kev sib raug zoo rau tej nta uas characterize lawv raws li ntsuas quantitatively los yog qualitatively.

Piv txwv li, yog hais tias muaj yog ib tug batch ntawm cov khoom, ntau sijhawm yuav ua tau qhov loj ntawm lub ntsiab lus ntawm cov qhua, thiab zoo - txheem qhov chaw.

Yog hais tias tsim nyog, mus saib lawv ua raws kev cai nrog tus qauv tej zaum chaw uasi mus rau ib tug tas mus li daim ntawv ntsuam xyuas, tab sis nyob rau hauv kev xyaum nws yog tsis tshua muaj siv. Piv txwv li, yog hais tias tus pejxeem muaj ib tug loj tus naj npawb ntawm cov khoom raug kawm, nws yog zoo tsis yooj yim sua rau kev ib tug census. Nyob rau hauv cov ntaub ntawv no, xaiv los ntawm cov totality ntawm ib tug tej yam muaj pes tsawg tus ntawm cov khoom (khoom) thiab soj ntsuam. Yog li, muaj ib tug general thiab cov qauv.

General yog lub teeb ntawm tag nrho cov khoom uas yog kev kawm mus rau kev soj ntsuam xyuas los yog kev kawm. Lub ntug, raws li ib tug txoj cai, muaj ib tug finite nab npawb ntawm cov ntsiab, tab sis yog hais tias nws yog loj heev, nyob rau hauv thiaj li yuav piv tau cov zauv nws yog lam xav hais tias cov totality muaj ib tug infinite tus naj npawb ntawm cov khoom.

Qauv los yog ib tug qauv set ntawm lub ntsiab yog lub feem xaiv los ntawm tag nrho cov teeb. Tus qauv yuav tsum yog pheej rov qab ua tsis repetitions. Nyob rau hauv thawj rooj plaub no nws yog rov qab mus rau hauv lub dav pejxeem, lub thib ob - tsis muaj. Nyob rau hauv kev xyaum, feem ntau siv repetition-free random xaiv.

General cov pej xeem thiab zauv yuav tsum tau txuas representativeness. Hais lus txawv, yog li ntawd tus yam ntxwv ntawm tag nrho cov qauv yuav confidently qhia hais tias tus totality ntawm cov tsos mob, nws yog tsim nyog tias cov zauv hais raws li meej raws li lawv tau. Nyob rau hauv lwm yam lus, tus qauv yuav tsum sawv cev (sawv cev).

Tus qauv yuav tsum ntau dua los yog tsawg tus neeg sawv cev, yog hais tias nws yog ua across los ntawm ib tug heev loj tus naj npawb ntawm cov totality. Nws yuav tsum tau sib cav nyob rau hauv lub hauv paus ntawm lub thiaj li hu ua kev cai lij choj ntawm cov coob. Nyob rau hauv cov ntaub ntawv no, tag nrho cov ntsiab muaj vaj huam sib luag yuav tau xaiv.

Muaj ntau ntau yam xaiv kev xaiv. Tag nrho ntawm cov kev muaj peev xwm nyob rau hauv tus muab faib ua ob qho kev xaiv:

• Option 1: xaiv ib tug caij, thaum cov pejxeem xwb yog tsis muab faib mus rau hauv qhov chaw. Los ntawm no embodiment tej zaum yuav muaj tej yam yooj yim random sampling tsis hloov re-xaiv.
• Kev Xaiv 2: Lub ntug yog muab faib mus rau hauv qhov chaw thiab cheebtsam raug xaiv. Qhov no yuav muaj xws li ib tug raug txhua yam thiab serial selections.

Tej yam yooj yim random - xaiv, nyob rau hauv uas lub ntsiab yog muab rho tawm ib tug los ntawm ib tug los ntawm tag nrho cov teeb across.

Raug - qhov no xaiv, nyob rau hauv uas lub ntsiab yog xaiv tsis yog los ntawm lub totality, thiab ntawm tag nrho nws cov "raug" qhov chaw.

Neeg kho tshuab - yog ib tug xaiv thaum tag nrho cov teeb yog cais rau ib tug xov tooj ntawm cov pab pawg sib npaug zos rau cov xov tooj ntawm cov ntsiab uas yuav tsum tau nyob rau hauv tus qauv, thiab chaw pib ntawm ib lub caij ntawm txhua pab pawg neeg yog xaiv. Piv txwv li, yog tias koj yuav tsum noj tam sim ntawd 25% ntawm qhov chaw, manufactured lub tshuab, ces xaiv txhua txhua plaub yam khoom, thiab yog hais tias koj xav mus noj tam sim ntawd 4% ntawm cov khoom, xaiv txhua yam ntawm nees nkaum-tsib, thiab li ntawm. Nws yog tsim nyog los hais tias tej zaum tus neeg kho tshuab xaiv tej zaum yuav tsis muab ib tug txaus tus neeg sawv cev qauv.

Serial - yog ib tug xaiv, nyob rau lub ntsiab yog raug xaiv los ntawm cov totality ntawm "batches", las tus nruam txoj kev tshawb no, es tsis yog ib tug. Piv txwv li, thaum ib tug loj tus naj npawb ntawm qhov chaw no yog ua los ntawm tsis siv neeg machine, hais tias ib tug kev suav pej xeem yog ua tau tsuas yog nrog rau kev hwm mus lawm ob peb machine. Serial kuaj siv thaum lub analyzed yam ntxwv muaj ib tug me me variation nyob rau hauv txawv series.

Yuav kom txo tau lub uas tsis muaj ntaub ntawv zauv-statistical txoj kev nrug muaj feem luj cov pejxeem ntawm cov xim. Ntxiv mus, xim tswj yuav ua tau tag nrho ob qho tib-theem thiab multi-theem, uas tsub kom lub ntseeg ntawm lub daim ntawv ntsuam xyuas.