༧ଌࢠ ̂ lp ln ̂ p 1 − ̂ p ϩδοτม ਖ਼ղϥϕϧ ϩδεςΟοΫճؼ ̂ o = 1 1 + exp{ − (a ⋅ ̂ lp + b)} w ֶश͞ΕͨϞσϧͷ༧ଌࢠΛͬͯͲͷఔϩδεςΟοΫճؼͰදݱͰ͖Δ͔ w ϩδεςΟοΫճؼ͕ਖ਼͍͠Ϟσϧɹͱ͍͏Ծఆ w ͕ʹۙ͘ɼ ͕ʹ͍ۙ a b ˠྑ͍֬ਪఆ ධՁํ๏cਖ਼ղ֬ͷਪఆɼ$PYͷํ๏
༧ଌࢠ ̂ lp ln ̂ p 1 − ̂ p ϩδοτม ਖ਼ղϥϕϧ ϩδεςΟοΫ(".ճؼ ̂ o = 1 1 + exp{ − (a ⋅ s( ̂ lp) + b)} w ϩδεςΟοΫճؼ͕ਖ਼͍͠Ϟσϧɹͱ͍͏Ծఆ ਪఆਖ਼ղ֬ ̂ o w ༧ଌ֬ ͱ ͷฏۉೋޡࠩ ̂ p ̂ o w εϓϥΠϯ ʹΑΓ֎Εʹॊೈͳճؼ s( ⋅ ) ධՁํ๏cਖ਼ղ֬ͷਪఆɼ&$*
)-౷ܭྔ ) $ ɼ&$&ɼ.$&ʢ$ʣΧϦϒϨʔγϣϯۂઢʢ$ʣ $PYɼ&$*ɼ*$* w ϩδεςΟοΫճؼ͕ྑ͍ϞσϧͱԾఆ͢Δσʔλɼͦ͏Ͱͳ͍σʔλ w σʔλൺɼɼ w Ϟσϧɿ ϩδεςΟοΫճؼɼϥϯμϜϑΥϨετʢ3'ʣɼଟύʔηϓτϩϯʢ.-1ʣɼ MJHIU(#.ʢ-(#.ʣ w USBJOσʔλͰֶशɼUFTUσʔλͰධՁ
)-౷ܭྔ ) $ ɼ&$&ɼ.$&ʢ$ʣΧϦϒϨʔγϣϯۂઢʢ$ʣ $PYɼ&$*ɼ*$* w ϩδεςΟοΫճؼ͕ྑ͍ϞσϧͱԾఆ͢Δσʔλɼͦ͏Ͱͳ͍σʔλ w σʔλൺɼɼ w Ϟσϧɿ w USBJOσʔλͰֶशɼUFTUσʔλͰධՁ ϩδεςΟοΫճؼɼϥϯμϜϑΥϨετʢ3'ʣɼଟύʔηϓτϩϯʢ.-1ʣɼ MJHIU(#.ʢ-(#.ʣ
ϩδεςΟοΫճؼ͕Ϟσϧͱͯ͠ྑ͍ͱ͢Δσʔλ w ઢܗ༧ଌࢠ ͱ͢Δɽʢ ܾΊଧͪʣ li = aXi + b a, b w ਖ਼ղ֬ Λઢܗ༧ଌࢠͷϩδεςΟοΫมͨ͠ͷͱ͢Δɼ͢ͳΘͪ pi pi = logistic(li ) = ln exp li 1 + exp li w ϩδεςΟοΫճؼ͕Ϟσϧͱͯ͠ྑ͍ͱ͠ͳ͍σʔλ w ઢܗ༧ଌࢠ ͱ͢Δɽʢ ܾΊଧͪʣ li = aXi + b a, b w ਖ਼ղ֬ Λ Λύϥϝʔλʹͭϕʔλ͔Βൃੜͤ͞Δ pi αi , βi w αi = logistic(li ), βi = logistic(li ) w ϥϕϧ ਖ਼ղ֬ ΛύϥϝʔλʹͭϕϧψʔΠ͔Βൃੜͤ͞Δɽ yi pi yi = Bernoulli(pi )