Qhov sib txawv tseem ceeb ntawm qhov nruab nrab thiab nruab nrab yog qhov txhais tau tias yog cov lej ntawm tag nrho cov txiaj ntsig hauv cov ntaub ntawv muab faib los ntawm tus lej ntawm tus nqi, thaum nruab nrab yog tus nqi nruab nrab ntawm cov ntaub ntawv teev.
Peb siv qhov nruab nrab thiab nruab nrab los xyuas qhov chaw ntawm cov ntaub ntawv vim tias lawv muab qhov qhia txog tus nqi nruab nrab nyob ib puag ncig uas cov txheej txheem muaj txiaj ntsig zoo rau pawg. Kev xaiv ntawm qhov nruab nrab lossis nruab nrab rau kev tshuaj xyuas cov ntaub ntawv nyob ntawm seb hom ntaub ntawv thiab qhov xav tau ntawm qhov tshwm sim. Qee zaum, txhais tau tias muab cov txiaj ntsig zoo dua li qhov nruab nrab thiab rov ua dua.
txhais tau li cas?
Lub tswv yim ntawm qhov txhais tau zoo ib yam li suav tus nqi nruab nrab ntawm cov ntaub ntawv teev. Hauv cov lus yooj yim, txhais tau tias yog cov lej ntawm tag nrho cov lej muaj nuj nqis tam sim no hauv cov ntaub ntawv muab faib los ntawm tus lej ntawm qhov tseem ceeb tam sim no hauv cov ntaub ntawv ntawd. Hom kev txhais no yog hu ua Arithmetic mean. Muaj peb chav kawm ntawm qhov txhais tau tias: Geometric txhais tau tias, Harmonic mean thiab Population mean.
Qhov geometric txhais tau tias yog siv rau cov lej zoo, uas tau txhais hauv cov ntaub ntawv teeb tsa raws li cov khoom lag luam es tsis yog cov lej. Lub harmonic txhais tau tias muaj txiaj ntsig zoo rau cov lej uas muaj qee qhov kev sib raug zoo nrog lub sij hawm muaj units xws li cov ntaub ntawv ntawm kev tshaj tawm lossis kev nrawm uas tau sau nyob rau lub sijhawm sib txawv. Ob qhov ceev thiab acceleration muaj units xws li m/s thiab m/sq.sec. Cov pej xeem txhais tau tias txawv ntawm tag nrho cov no txhais tau tias nws yog qhov xav tau ntawm tus nqi sib txawv, suav los ntawm qhov hnyav nruab nrab ntawm txhua qhov ua tau.
Median yog dab tsi?
Median ntawm cov ntaub ntawv teev yog tus lej nruab nrab tus nqi, uas cais cov ntaub ntawv ib nrab qis los ntawm cov ntaub ntawv ib nrab sab saud. Txoj kev nrhiav tus nruab nrab yog qhov yooj yim heev. Tsuas yog npaj tag nrho cov txiaj ntsig ntawm cov ntaub ntawv muab rau hauv qhov kev txiav txim nce; uas yog, pib ntawm qhov tsawg kawg nkaus tus nqi thiab xaus ntawm tus nqi siab tshaj plaws. Tam sim no tus nqi nruab nrab yog koj qhov nruab nrab.
Yog tias tus lej ntawm qhov tseem ceeb hauv koj cov ntaub ntawv teev yog tus lej sib npaug, ces qhov nruab nrab ntawm ob qhov tseem ceeb yuav yog koj qhov nruab nrab. Thaum muaj qhov ua tau ntawm asymmetry hauv kev faib lossis qhov kawg tsis tau muab, qhov nruab nrab yuav pab tau rau kev ntsuas qhov chaw. Yog li ntawd, qhov nruab nrab yog qhov zoo dua ntawm kev ntsuas lub hauv paus nyiam, yog tias ob peb qhov tseem ceeb tau muab cais tawm ntawm lub cev tseem ceeb ntawm cov ntaub ntawv (hu ua outliers).
Dab tsi yog qhov txawv ntawm Mean thiab Median?
Mean yog tus nqi nruab nrab ntawm cov ntaub ntawv teev tseg, thaum nruab nrab yog tus lej nruab nrab ntawm cov ntaub ntawv teev. Qhov no yog qhov txawv ntawm qhov nruab nrab thiab nruab nrab. Txhawm rau nrhiav qhov nruab nrab, koj yuav tsum ntxiv tag nrho cov txiaj ntsig ntawm cov ntaub ntawv teeb tsa ua ke thiab faib cov lej no los ntawm tus lej ntawm qhov tseem ceeb hauv cov ntaub ntawv teev. Txawm li cas los xij, txhawm rau nrhiav qhov nruab nrab, koj yuav tsum npaj txhua qhov tseem ceeb hauv cov ntaub ntawv teev nyob rau hauv qhov kev txiav txim nce mus, thiab txiav txim siab seb tus nqi twg yog qhov nruab nrab.
Kom tshem tawm qhov sib txawv ntawm qhov nruab nrab thiab nruab nrab, ntawm no yog ib qho piv txwv:
Peb muaj cov ntaub ntawv teeb tsa uas suav nrog cov txiaj ntsig xws li 5, 10, 15, 20 thiab 25. Tam sim no peb suav cov ntsiab lus thiab qhov nruab nrab rau cov ntaub ntawv no.
Mean=60 + 80 + 85 + 90 + 100=415/5=83
Median=85 vim nws yog tus lej nruab nrab ntawm cov ntaub ntawv no.
Tsis tas li ntawd, txhais tau tias feem ntau yog qhov kev ntsuas tsim nyog tshaj plaws ntawm qhov chaw. Qhov no yog vim nws yuav siv sij hawm rau hauv tus account txhua tus nqi hauv cov ntaub ntawv teev. Txawm li cas los xij, outliers hauv cov ntaub ntawv teeb tsa tuaj yeem cuam tshuam qhov txhais tau tias, ua rau nws tsis yog sawv cev rau tag nrho cov qhab nia. Hauv qhov no, qhov nruab nrab yog ib qho kev ntsuas zoo dua vim tias cov khoom siv tsis cuam tshuam rau nws.
Summary – Mean vs Median
Mean thiab nruab nrab yog ntsuas uas pab txhais cov ntaub ntawv sau los ntawm ib qhov chaw. Txawm hais tias muaj coob tus neeg tseem tsis meej pem txog ob lub ntsiab lus no, muaj qhov sib txawv ntawm cov ntsiab lus thiab kev tshaj tawm. Qhov nruab nrab yog tus nqi nruab nrab ntawm cov ntaub ntawv teev thaum nruab nrab yog tus lej nruab nrab ntawm cov ntaub ntawv teev.
Image Courtesy:
1. "Kev sib piv txhais tau tias hom nruab nrab" Los ntawm Cmglee - Tus kheej ua haujlwm (CC BY-SA 3.0) ntawm Commons Wikimedia
2. "Nrhiav qhov nruab nrab" Los ntawm Blythwood - Tus kheej ua haujlwm (CC BY-SA 4.0) ntawm Commons Wikimedia
