powerprep的打分让我很疑惑

raw score | scaled score | percentile rank

30 ------------ 55 ---------- 99

29 ------------ 54 ---------- 98

28 ---------- 52-53 --------- 97

27 ---------- 50-51 --------- 95-96

26 ---------- 48-49 --------- 91-94

25 ---------- 46-47 --------- 87-90

24 --------- - 44-45 --------- 83-86

23 ---------- 42-43 --------- 77-82

22 ---------- 40-41 --------- 72-76

21 ---------- 38-39 --------- 67-71

20 ---------- 36-37 --------- 62-66

19 ---------- 34-35 --------- 53-61

18 ---------- 32-33 --------- 45-52

17 ---------- 30-31 --------- 39-44

16 ---------- 28-29 --------- 34-38

15 ---------- 26-27 --------- 30-33

14 ---------- 24-25 --------- 26-29

13 ---------- 22-23 --------- 22-25

12 ---------- 20-21 --------- 19-21

11 --------- - 18-19 --------- 16-18

10 ---------- 16-17 --------- 13-15

9 ----------- 14-15 --------- 10-12

8 ----------- 12-13 --------- 7-9

7 ----------- 10-11 --------- 5-6

5-6 ---------- 8-9 ---------- 3-4

0-4 ---------- 6-7 ---------- 0-2