I'm looking at analyzing the just noticeable differences (JNDs) in temporal order judgment (TOJ) studies. A modern way to do this is with a multilevel model. And, I am going to do that. But I also need to actually extract and analyze JNDs by participant in a more traditional way.
I'm doing it by generating a logistic regression for each participant with whether X was selected as first as the response and the TTOA (target-target SOA) as the predictor. Then I go through the model function and find the TTOA for when the probability of selecting X first is just less than 25% and when it is just greater than 75%. The difference between those two TTOAs is 2 x JND.
But what do people do when the found values from the regression are actually outside the times used in the experiment? Or, what does one do if the function seems excessively shifted so that the point of subject simultaneity is well off centre?
I'd be happy for a pointer to where this sort of analysis is explained as well.