This Moodle quiz reporting module provides bespoke reports for the STACK question type. (https://github.com/maths/quiz_stack/). It was created by Tim Hunt and Chris Sangwin. STACK is an open-source system for computer-aided assessment in Mathematics and related disciplines, with emphasis on formative assessment.
Note, this is experimental code. In particular, the features will change, and some of the numbers returned are not accurate counts of numbers of students' attempts.
To install, either download the zip file,
unzip it, and place it in the directory moodle\mod\quiz\report\stack.
(You will need to rename the directory quiz_stack -> stack.)
Alternatively, get the code using git by running the following command in the
top level folder of your Moodle install:
git clone git://github.com/maths/quiz_stack.git mod/quiz/report/stack
For full install instructions, see the STACK install instructions.