hello
I simply tested the first data set
when you do : impFatigueA = importdata('Fatigue_A.txt');
impFatigueA is a structure (containers)
to access the numerical data you have to dive a bit deeper
data1 = impFatigueA.data;
then you can take the abs of your data - I don't know yet which of the 16 columns you want to take the abs of it
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/818584/image.png)