Need help with Storyline 1 variables in a multiple choice quiz

Hi!  I'm pretty new to Storyline and could really use a little help.

I've got a 15-question multiple choice quiz, all of whose questions go to a results slide at the end. After the results slide, I'd like to have my own detailed analysis of what a student needs to work on. 

I've got about 8 topics a student might need to review (Some of the 15 questions count as being about the same topic.)  On the title slide I made variables for each topic and set them all to TRUE (meaning a student is OK on that topic).  Whenever a student gets one wrong in that topic, I want to flip that variable to FALSE (meaning a student has not mastered that topic).  (I want to do that not when a student is reviewing her answers but only the first time around when she's taking the test.)  I tried doing that for the first few questions by adjusting the variable on the Incorrect layer.  I expected on my analysis page to be able to use the TRUE/FALSE to indicate what topics a student had or hadn't mastered. However, the variables never switch from TRUE to FALSE.  Since I don't have feedback along the way but only at the end when a student hits the SUBMIT button just once, I think the Correct and Incorrect layers of each question don't even get activated. The result is that my variables don't get flipped.

I want students to be able to skip questions temporarily, do them in whatever order they want, etc, which is why I didn't have a SUBMIT button on each question but only after all 15 questions.  But I can't figure out how to keep feedback only at the end and yet flip variables for individual wrong answers along the way. 

I've attached my Storyline file.  Unfortunately, I've still got just Storyline 1, so I can't read anything any sample code written in Storyline 2.  :-(

Any help would be very much appreciated!

Dorothy Stark