Nyob rau hauv txoj kev xav yuav tshwm sim, qhov kev sib tw-ib txwm (lossis qhov tsis sib xws) yog qhov qhov tshwm sim tsis tu ncua ntawm qhov sib txawv tsis sib xws uas nws cov logarithm ib txwm faib. … Cov txheej txheem log-ib txwm yog qhov kev txheeb xyuas qhov tseeb ntawm cov khoom sib npaug ntawm ntau qhov kev ywj pheej sib txawv, txhua qhov zoo.
Puas lognormal faib tib yam li ib txwm faib?
Qhov kev faib tawm tsis zoo sib txawv ntawm qhov kev faib tawm ib txwm muaj ntau txoj hauv kev. Qhov sib txawv loj yog nyob rau hauv nws cov duab: qhov ib txwm faib yog symmetrical, whereas lub lognormal faib tsis yog Vim tias qhov tseem ceeb hauv qhov kev faib tawm tsis zoo yog qhov zoo, lawv tsim txoj cai-skewed nkhaus.
Dab tsi yog ob qhov tsis sib xws ntawm kev faib khoom tsis raug?
Lub lognormal faib muaj ob yam, μ, thiab σ. Cov no tsis zoo ib yam li qhov txhais tau tias thiab tus qauv sib txawv, uas yog cov ntsiab lus ntawm lwm tus tshaj tawm, tab sis lawv tau piav qhia txog kev faib tawm, suav nrog kev ntseeg siab ua haujlwm.
Dab tsi yog qhov ntsuas ntawm qhov kev faib tawm tsis raug?
Skewed distributions with low mean values, loj variance, and all-positive values feem ntau haum rau hom kev faib. Cov nqi yuav tsum yog qhov zoo vim tias log(x) tsuas muaj rau qhov zoo ntawm x. Cov duab ntawm lub lognormal faib yog txhais los ntawm peb qhov tsis muaj: σ, cov duab parameter
Dab tsi ua rau kev faib khoom tsis raug cai?
Lognormal distributions feem ntau tshwm sim thaum muaj qhov qis qis nrog qhov sib txawv loj, thiab thaum qhov tseem ceeb tsis tuaj yeem tsawg dua xoom. Kev faib tawm ntawm cov txiaj ntsig nyoos yog li skewed, nrog rau tus Tsov tus tw txuas ntxiv zoo ib yam li tus Tsov tus tw pom nyob rau hauv nplai-dawb thiab broad-scale systems.
