s

{1}

{1,2}

{1,3}

$v\left(s\right)$

2

14

10

20

$v\left(s\backslash 1\right)$

0

2

2

8

$v\left(s\right)-v\left(s\backslash 1\right)$

2

12

8

12

$\left|s\right|$

1

2

2

3

$w\left(\left|s\right|\right)$

1/3

1/6

1/6

1/3

$w\left(\left|s\right|\right)\left[v\left(s\right)-v\left(s\backslash 1\right)\right]$

2/3

2

4/3

4