Simple version of the law of iterated expectations (los ntawm Wooldridge's Econometric Analysis of Cross Section and Panel Data, p. 29): E(y)=Ex[E(y|x)]. Ntawd yog, E(y) tsuas yog qhov hnyav nruab nrab ntawm qhov E(y|x=cj), qhov twg qhov hnyav pj yog qhov tshwm sim uas x siv rau tus nqi ntawm cj.
Yuav ua li cas yog lub mis rau kev cia siab?
Tus nqi tsim nyog tus nqi yog qhov qhov tshwm sim ntawm qhov tshwm sim tau muab los ntawm tus nqi ntawm lub sijhawm qhov xwm txheej tshwm sim: (P(x)n). Cov mis hloov me ntsis raws li hom xwm txheej tshwm sim.
Txoj cai ntawm kev cia siab rov qab ua li cas?
Txoj Cai Lij Choj Kev Cia Siab hais tias tus nqi xav tau ntawm qhov sib txawv ntawm qhov sib txawv yog sib npaug rau cov txiaj ntsig ntawm qhov xav tau ntawm qhov sib txawv ntawm qhov sib txawv ntawm qhov sib txawv thib ob.
Dab tsi yog linearity ntawm kev cia siab?
Linearity of expectation is the khoom uas tus nqi xav tau ntawm cov lej ntawm qhov sib txawv ntawm qhov sib txawv yog sib npaug rau cov lej ntawm lawv tus kheej xav tau qhov tseem ceeb, tsis hais seb lawv puas muaj kev ywj pheej. Tus nqi xav tau ntawm qhov sib txawv ntawm qhov sib txawv yog qhov tseem ceeb ntawm qhov ntsuas qhov nruab nrab ntawm qhov ua tau.
Txoj cai ntawm kev cia siab yog dab tsi?
Txoj cai ntawm kev cia siab hais tias koj yuav tsis tau ntau tshaj qhov koj xav tau ntawm lub neej. Yog tias koj xav tau yam me me, koj yuav tau txais yam me. Yog tias koj xav tau yam loj, koj yuav tau txais yam loj dua.
