Lookup function

---

Knowing that q was measured from z which include the levels values as well . like the example 

????????????????????????????????????

There is no example which would make it any clearer and there is no q, neither a scalar nor a vector in your worksheet!!??

If q is the second column of the data you read in (unit MPa), then it can be seen that the values are not in ascending order. So one specific q-value like 32 MPa could be assigned to a lot of different depth values in d which then correspond to different 'level' (however you would like to define a 'level').

Please be more specific as to what you are trying to achieve and give some concrete numeric examples in the Prime worksheet - by this I mean trhat you clearly should name the vectors being involved, name the specific numeric value(s) you choose as input example and also name the result you expect. And if the result is a level number, you should also explain why its this number and how we would arrive at it.

You may also want to look up the syntax of the "lookup" function in the help and compare with your usage of it.

The second and third arguments must be both vectors(!) of equal dimension, the first one usually is a scalar value.