1) The way you have your ER Diagram drawn, each studies record will have a course foreign key. From the course entity, you can find out which student is associated with the studies record. In other word, to get from the studies entity to the student entity, you have to go through the course entity. The problem with this is that if the student is taking a module that is not within his course, then there is no course record to go from the studies entity to the student entity.

2) To track the facilities needed for each module, there will need to be a many-to-many relationship from the module entity to the facilities entity.

3) I was thinking that credits can be recorded as an attribute in the studies entity. Since each module the student passes counts as one credit and since the studies entity tracks which modules the student is taking, I would add an attribute in the studies entity that tracks whether the student has passed the module or not.

4) My thinking with this point is that each module contains lectures and each lecture is taught by a tutor. Therefore, I would remove the relationship between the tutor and the module and replace it with a relationship between the module and the lecture. With the way you have things set up, I think there will be an issue if the tutor for a module changes sometime during the module.

Personally, 18 entities seems high; however, I will have to review the requirements again to see how many entities I would use. I'll have to get back to you on that.