D 6y qwurs 6 6 y 28 another illustrative example

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Unformatted text preview: DN 6WURQJ 1RUPDO 6WURQJ <HV ( +LJK :HDN 1R ( ( 1RUPDO :HDN <HV 1RUPDO :HDN <HV 1RUPDO 6WURQJ <HV +LJK 6WURQJ <HV 1RUPDO :HDN <HV +LJK 6WURQJ 1R +LJK ( 1RUPDO ( +LJK ( 1RUPDO ( ,* 6 _ D = (QWURS\ 6 − ¦ Y∈YDOXHV D _ 6Y _ (QWURS\ 6 _6_ Y ,* 6 _ D = (QWURS\ 6 − 27 ¦ Y∈YDOXHV D _ 6Y _ (QWURS\ 6 _6_ Y 28 Another Illustrative Example +XPLGLW\ +XPLGLW\ :LQG 3OD\7HQQLV +LJK :HDN 1R +LJK 6WURQJ 1R :LQG +LJK :HDN <HV +LJK :HDN <HV 1RUPDO :HDN <HV 1R :HDN 6WURQJ 1RUPDO 6WURQJ 1RUPDO 6WURQJ <HV ( +LJK :HDN 1R ( ( 1RUPDO :HDN <HV 1RUPDO :HDN <HV 1RUPDO 6WURQJ <HV +LJK 6WURQJ <HV 1RUPDO :HDN <HV +LJK 6WURQJ 1R Another Illustrative Example +XPLGLW\ :LQG 3OD\7HQQLV +LJK :HDN 1R +LJK 6WURQJ 1R +XPLGLW\ :LQG +LJK :HDN <HV +LJK :HDN <HV 1RUPDO :HDN <HV 1R +LJK 1RUPDO :HDN 6WURQJ 1RUPDO 6WURQJ 1RUPDO 6WURQJ <HV ( +LJK :HDN 1R ( ( ( ( 1RUPDO :HDN <HV 1RUPDO :HDN <HV ,* 6 _ +XPLGLW\ ,* 6 _ :LQG 1RUPDO 6WURQJ <HV +LJK 6WURQJ <HV 1RUPDO :HDN <HV +LJK 6WURQJ 1R ,* 6 _ D = (QWURS\ 6 − 29 +LJK ( 1RUPDO ( ,* 6 _ +XPLGLW\ ,* 6 _ D = (QWURS\ 6 − ¦ Y∈YDOXHV D _ 6Y _ (QWURS\ 6 _6_ Y ¦ Y∈YDOXHV D _ 6Y _ (QWURS\ 6 _6_ Y 30 Another Illustrative Example ,* 6 _ +XPLGLW\ 2XWORRN ,* 6 _ :LQG ,* 6 _ 7HPSHUDWXUH ,* 6 _ 2XWORRN 6XQQ\ Another Illustrative Example 'D\ 2XWORRN 3OD\7HQQLV 2XWORRN 6XQQ\ 6XQQ\ 2YHUFDVW 5DLQ 5DLQ 5DLQ 2YHUFDVW 6XQQ\ 6XQQ\ 5DLQ 6XQQ\ 2YHUFDVW 2YHUFDVW 5DLQ 1R 1R <HV <HV <HV 1R <HV 1R <HV <HV <HV <HV <HV 1R 32 2YHUFDVW 5DLQ " <HV " 31 Another Illustrative Example 2XWORRN 'D\ 2XWORRN 3OD\7HQQLV 6XQQ\ 6XQQ\ 2YHUFDVW 5DLQ 5DLQ 5DLQ 2YHUFDVW 6XQQ\ 6XQQ\ 5DLQ 6XQQ\ 2YHUFDVW 2YHUFDVW 5DLQ 1R 1R <HV <HV <HV 1R <HV 1R <HV <HV <HV <HV <HV 1R Another Illustrative Example 2XWORRN ,* 6VXQQ\ _ +XPLGLW\ = ,* 6VXQQ\ _ 7HPS = ,* 6VXQQ\ _ :LQG = 6XQQ\ 2YHUFDVW 5DLQ 6XQQ\ 2YHUFDVW 5DLQ " <HV " " <HV " 3OD\7HQQLV 1R 1R 1R <HV <HV 34 &RQWLQXH XQWLO ‡ (YHU\ DWWULEXWH LV LQFOXGHG LQ SDWK RU ‡ $OO H[DPSOHV LQ WKH OHDI KDYH VDPH ODEHO 'D\ 2XWORRN 7HPSHUDWXUH +XPLGLW\ :LQG 6XQQ\ +RW +LJK :HDN 6XQQ\ +RW +LJK 6WURQJ 6XQQ\ 0LOG +LJK :HDN 6XQQ\ &RRO 1RUPDO :HDN 6XQQ\ 0LOG 1RUPDO 6WURQJ 33 Another Illustrative Example 2XWORRN Another Illustrative Example 2XWORRN 6XQQ\ 2YHUFDVW 5DLQ 6XQQ\ 2YHUFDVW 5DLQ " <HV " +LJK 1R +XPLGLW\ 1RUPDO <HV <HV " 35 36 Another Illustrative Example 2XWORRN Basic Questions • How to choose the attribute/value to split on at each level of the tree? 6XQQ\ 2YHUFDVW 5DLQ • When to stop splitting? When should a node be declared a leaf? • If a leaf node is impure, how should the class label be assigned? :HDN <HV +XPLGLW\ +LJK 1R 1RUPDO <HV <HV :LQG 6WURQJ 1R • If the tree is too large, how can it be pruned? 37 38 Pure and Impure Leaves and When to Stop Splitting All the data in the node comes from a single class. We declare the node to be a leaf and stop splitting. Thi...
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This note was uploaded on 11/03/2010 for the course UNIVERSITY CS6375 taught by Professor Vicentng during the Fall '10 term at University of Texas at Dallas, Richardson.

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