R help - Jul 2011 - Calculate Az (A sub z) with R?

I am looking for (or interested in writing) a function that calculates Az, an
alternative measure of discriminability from SDT (alternative to d', Az). I
have written my own functions for d', A', B"d, and am aware of the
'sdtalt'
package, but I have yet to find a way to calculate Az, since it require the
phi operator.

For a relevant paper/discussion (and formula), please see Verde and
McMillian, 2006 (Measures of sensitivity based on a single hit rate and
false alarm rate: The accuracy, precision, and robustness of d', Az, and Az)

Any help on this would be greatly appreciated!

David Dobolyi
Graduate Student
Cognitive Psychology
University of Virginia

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dd2es <dd2es <at> virginia.edu> writes:
>
> I am looking for (or interested in writing) a function that calculates Az,
> an alternative measure of discriminability from SDT (alternative to d',
Az).
> I have written my own functions for d', A', B"d, and am aware
of the 'sdtalt'
> package, but I have yet to find a way to calculate Az, since it require the
> phi operator.
The Phi --- not Psi, see the paper --- function is simply the cumulative
normal distribution, so you can use pnorm() instead.

-- ?Hans Werner
> For a relevant paper/discussion (and formula), please see Verde and
> McMillian, 2006 (Measures of sensitivity based on a single hit rate and
> false alarm rate: The accuracy, precision, and robustness of d', Az,
and Az)
>
> Any help on this would be greatly appreciated!
>
> David Dobolyi
> Graduate Student
> Cognitive Psychology
> University of Virginia
>