| Name  |     ID | 1.1    | 1.2 | 1.3 | 1.4 | 2.1 | 2.2 | 2.3 | 2.4 | 2.5 | Extra |   |   |
| Sum   |   Mark |        |     |     |     |     |     |     |     |     |       |   |   |
|-------+--------+--------+-----+-----+-----+-----+-----+-----+-----+-----+-------+---+---|
| Name1 | 111111 | 10     |  10 |  10 |  12 |  12 |   3 |   4 |  12 |   3 |       | 1 | 5 |
| 2     |     78 | #ERROR |     |     |     |     |     |     |     |     |       | 2 | 5 |
| Name2 |  22222 |        |     |     |     |     |     |     |     |     |       | 3 | 5 |
|       |      0 | #ERROR |     |     |     |     |     |     |     |     |       | 4 | 5 |
| Name3 |  33333 |        |     |     |     |     |     |     |     |     |       | 5 | 5 |
|       |      0 | #ERROR |     |     |     |     |     |     |     |     |       | 6 | 5 |
#+TBLFM: $14='(sbe score2mark (score $13) (passscore "50"))

#+name: score2mark
#+begin_src python :var score=0 :var passscore=0
def score2mark(score, passscore):
    marklist = [5, 4.3, 4, 3.7, 3.3, 3, 2.7 ,2.3, 2, 1.7, 1.3, 1]
    step=(100-passscore)/(len(marklist)-1)
    if  score < passscore:
           return marklist[0]
    for mark in marklist[1:]:
           if round(passscore) <= score <= round(passscore+step):
               return mark
           else:
                  passscore += step
    return -1

return score2mark(score, passscore)
#+end_src