IBT托福作文写作考试分数到底是怎么换算的？

具体是这样的：

5.00                   30

 4.75                   29

 4.50                   28

 4.25                   27

 4.00                   25

 3.75                   24

 3.50                   22

 3.25                   21

 3.00                   20

 2.75                   18

 2.50                   17

 2.25                   15

 2.00                   14

 1.75                   12

 1.50                   11

 1.25                   10

 1.00                   8