[ACT-R-users] Question about chunk recall times

[Rhiannon L Weaver]

In the Atomic Components of thought book it is mentioned that using the 
equation RT = Fe^{-(A + epsilon)} yields a Weibull distribution for chunk 
recall times (where RT = "retrieval time" and A + epsilon = noisy 
activation of the chunk).  

Can someone point me to a proof of this?  I am wondering if the 
distribution arises conditional on the chunk being chosen?  If I do a 
straight transformation of variables assuming the variation comes from the 
logistic epsilon, I don't get a Weibull distribution, I get something 
else, something that looks like quadratic decay in time.  Help?

Thanks,
-Rh

Rhiannon Weaver
PhD student, Statistics
Carnegie Mellon University

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