D e c i s io n T r e e
A tt r ib u t e : O u t lo o k ( + 9 ,- 5 )
= ◦
I
E ( E n tr o p y ) = # 1 09 2 ( ¼ ) - ¥ 1 9 2 ( I ) - •
✗
•
= 0 .9 4
/ a
( i) S u n n y ( + 2 ,- 3 ) - ◦
- •
E s u n n y = - ⅔ l o g z ( 2 5 ) - 3 1 9 2 ( ⅔ ) o
•
= 0 .9 7 1
= •
C i i) R a in ( + 3 ,- 2 ) ◦
E r a in = - 3 g l o g s ( ¾ ) - 3 1 0 9 2 ( ⅔ ) =
o
= 0 .9 7 1
i n ) O v e r c a s t ( 4 ,0 )
•
✗
• o
E o v e r c a s .tn - 0
G a in = E n tro p y - Σ Ed ✗ E n tr op y
= E n tr o p y - F g ✗ E n tr op y ( F u n ny ) - # E n tr op y ( F o r e c a st) - I , E n tr o p y E r a in )
= 0 .9 4 - 5 4 × 0 .9 7 1 - 5 4 × 0 .9 7 1 - °
= 0 .2 4 6 4
A tt r ib u t e : T e m p .
v a lu e s → n o t , m ild , c o o l
[ t e m p = ⇒ ✗ l o g 26 % 1 - ¾ 1 0 9 2 ( ¼ )
= 0 .9 4
A tt r ib u t e : O u t lo o k ( + 9 ,- 5 )
= ◦
I
E ( E n tr o p y ) = # 1 09 2 ( ¼ ) - ¥ 1 9 2 ( I ) - •
✗
•
= 0 .9 4
/ a
( i) S u n n y ( + 2 ,- 3 ) - ◦
- •
E s u n n y = - ⅔ l o g z ( 2 5 ) - 3 1 9 2 ( ⅔ ) o
•
= 0 .9 7 1
= •
C i i) R a in ( + 3 ,- 2 ) ◦
E r a in = - 3 g l o g s ( ¾ ) - 3 1 0 9 2 ( ⅔ ) =
o
= 0 .9 7 1
i n ) O v e r c a s t ( 4 ,0 )
•
✗
• o
E o v e r c a s .tn - 0
G a in = E n tro p y - Σ Ed ✗ E n tr op y
= E n tr o p y - F g ✗ E n tr op y ( F u n ny ) - # E n tr op y ( F o r e c a st) - I , E n tr o p y E r a in )
= 0 .9 4 - 5 4 × 0 .9 7 1 - 5 4 × 0 .9 7 1 - °
= 0 .2 4 6 4
A tt r ib u t e : T e m p .
v a lu e s → n o t , m ild , c o o l
[ t e m p = ⇒ ✗ l o g 26 % 1 - ¾ 1 0 9 2 ( ¼ )
= 0 .9 4
