请教单侧公差非正态数据怎样统计Cpk

调角器解锁力要求数据<6，实际数据均为4和5，请问用什么工具来计算Cpk,另外通过什么手段来提高Cpk值

1 2 3 4 5
1 4.0 5.0 4.0 5.0 4.0
2 5.0 4.0 5.0 4.0 4.0
3 5.0 5.0 4.0 4.0 5.0
4 5.0 5.0 4.0 4.0 4.0
5 4.0 4.0 5.0 4.0 5.0
6 5.0 4.0 5.0 4.0 4.0
7 4.0 4.0 5.0 5.0 5.0
8 4.0 5.0 5.0 4.0 5.0
9 4.0 5.0 5.0 5.0 4.0
10 5.0 4.0 4.0 4.0 4.0
11 5.0 4.0 4.0 4.0 5.0
12 5.0 4.0 5.0 4.0 5.0
13 5.0 4.0 5.0 5.0 4.0
14 4.0 4.0 5.0 5.0 4.0
15 5.0 5.0 4.0 5.0 4.0
16 4.0 4.0 5.0 4.0 5.0
17 5.0 4.0 4.0 5.0 4.0
18 4.0 5.0 4.0 4.0 5.0
19 5.0 5.0 4.0 5.0 5.0
20 5.0 4.0 5.0 5.0 5.0
21 5.0 4.0 5.0 5.0 4.0
22 4.0 5.0 5.0 4.0 4.0
23 5.0 4.0 5.0 4.0 4.0
24 5.0 4.0 4.0 5.0 5.0
25 4.0 5.0 5.0 4.0 4.0