Thank you for interest.
No, I have not deleted any users from the course which is valid for evaluating.
I have just upgraded my earlier moodle version to 3.7 to be able to see the details of the new machine learning algorithms, mainly the the way of calculating the values of indicators from the moodle raw data and getting the data for other machine learning softwares. I am a professor of Applied Statistics at a university so I am not a real a moodle expert. (However I run my own moodle as an administrator for my courses.)
I set the end dates of all the other courses to remain only one course to be evaluated as a trial. This course was finished in July with 20 students. Many of them are not active students any more but still valid. I set the minimum requirement in the gradebook and used the PHP model "Minimum grade to pass the course". I used 24 indicators mainly using learning activities rather than social ones. In the evaluation process the algoritm always stopped indicating the "invalid users".
My suspect is that this Analytics can handle only the course data originated in the new 3.7 version and not capable handling courses finished in a previous version. Is that possible? The reason why I think is that I tried to start a brand new course in 3.7 and to produce new course data and in this case moodle reaction was "not valid sample data to analyze" and not the "invalid users". May be the log data were not enough (I could produce only 3 fake students data in this trial.)
Dear Elizabeth, what do you think?
Looking forward to any comments.