Lets say you have 10 participants, so a total of 100 dataset. I'll assume you already have your id, taskno, treatno and choice as column vectors. Now you have to create another vector dummy_1 (all zeros initially) which will be populated based on the condition fulfilment as given in your problem statement. Then a conditional loop something like this should work:
n=1;
for i=10:10:100
for j=n:i
if treatno(j,1)==1 && choice(j,1)==2
for m=j+1:i
dummy_1(m,1)=1;
end
n=n+10;
break
end
end
end
Now since I dont have the data, I have not tested it. I just typed it based on context. Hope this works! Let me know if you get stuck or the code throws any error.
