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algorithms to evaluate user responses

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I'm working on a web application which will be used for classifying photos of automobiles. The users will be presented with photos of various vehicles, and will be asked to answer a series of questions about what they see. The results will be recorded to a database, averaged, and displayed.

I'm looking for algorithms to help me identify users which frequently don't vote with the group, indicating that they're probably either not paying attention to the photos, or that they're lying about what they see. I then want to exclude these users, and recalculate the results, such that I can say, with a known amount of confidence, that this particular photo shows a vehicle that is this and that.

This question goes out to all you computer science guys, where to find such algorithms or to give myself the theoretical background to design such algorithms. I'm assuming I'm going to have to learn some probability and statics, maybe some data mining. Some book recommendations would be great. Thanks!

P.S. These are multiple choice questions.

All of these are good suggestions. Thank you! I wish there was a way on stack overflow to select multiple correct answers so more of you could be acknowledged for your contributions!!

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Ralph Avatar asked Nov 01 '09 19:11

Ralph


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2 Answers

I believe what you described is solved using outlier/anomaly detection. A number of techniques exist:

  • statistical-based methods
  • distance-based methods
  • model-based methods

I suggest you take a look at these slides from the excellent book Introduction to Data Mining

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Amro Avatar answered Sep 26 '22 03:09

Amro


Read The Elements of Statistical Learning, it is a great compendium on data mining.

You can be interested especially in unsupervised algorithms, for example clustering. Assuming that most people do not lie, the biggest cluster is right and the rest is wrong. Mark people accordingly, then apply some bayesian statistics and you'll be done.

Of course, most data mining technologies are pretty experimentative, so don't count on that they will be always right... or even in most cases.

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liori Avatar answered Sep 26 '22 03:09

liori