About This Book
If you need to know it, it’s in this book.
Cracking the GRE, 2013 Edition has everything you need to know to master Verbal Reasoning, Quantitative Reasoning, and the Essay sections of the GRE, and includes:
• Access to 4 full-length practice tests
• Practice questions with detailed explanations for every question
• Key strategies for solving Text Completions, Sentence Equivalence, Numeric Entry, Quantitative Comparisons, and more
• Thorough review of all GRE topics, including everything on the revised GRE that debuted in fall 2011
• Online video tutorials offering in-depth exploration of key strategies and concepts
This book is great to use for independent studying or to supplement GRE tutoring.
The trouble is, if lots of people get a question wrong, you don't know whether it's because it's a hard question (which is what you want), or because it's a bad question (poorly worded, misleading, or maybe even with the wrong answer marked as "right").
Standardized tests, like the GRE, put new questions on the test alongside old questions, to make sure that the kinds of people who get them right are also the kinds of people who got good scores with the old questions. If you don't have something similar, then I'd hesitate to trust any automatic ranking algorithm.
So if you want to proceed with this, you'll need, at a minimum, some automated way to figure out the difference between hard questions and good questions. That's going beyond programming, and more into math and statistics. I don't pretend to be an expert in either subject, but here are a few things that you might find interesting:
The Princeton Review's "Cracking the GRE" books explain how the GRE field-tests new questions. (Or at least they did several years ago, before the GRE went completely over to computerized adaptive testing. If newer editions turn out not to be helpful, see if you can find some older editions.) The Princeton Review GRE Web site might also have some useful information.
Wikipedia has articles on computerized adaptive testing and regression analysis that might be useful.
Also check out the mathematics StackExchange and the statistics StackExchange.