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

[Rhiannon L Weaver]

Hi Chris,

That is the equation I get as well.  It simplifies to a polynomial in x if 
you rearrange the exponents.   I talked with John about this and I think I 
understand it a little bit better now.  The Weibull distribution is coming 
from the Gumbel approximation to the distribution of a maximum of 
logistics.  So I guess it is saying, the distribution of the retrieval 
time, conditional on the fact that the chosen value was a maximum of 
competing values, is approximated by the Weibull.  I think, as you noted, 
the approximation is better when the activations of the chunks are close.  

Thanks for your input!

-Rh

On Tue, 27 Dec 2005, Chris R. Sims wrote:

> Rhiannon,
> 
> When I do the transformation I get the following for the PDF of  
> retrieval latencies, conditional on a chunk being selected:
> 
> 

Rhiannon Weaver
PhD student, Statistics
Carnegie Mellon University

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