Hi Dave,
I've created a function for this, and the code is below.
I hope you find it helpful.
:-)
Nestor
*****************************************************
Nestor Matthews, Ph.D.
Assistant Professor
Department of Psychology
Denison University
100 South Road
Knapp Hall, Room 505A
Granville, OH 43023 USA
Phone: (740) 587-5782
Fax: (740) 587-5675
E-mail:
matthewsn@...
http://www.denison.edu/psych/profbios/matthews.shtml
And
http://www.denison.edu/~matthewsn/index.html
*****************************************************
Here is the function's code
function d=dPrimeCalculation(proportionOfHits, proportionOfFAs)
%DPPRIMECALCULATION takes in the proportion of hits, and the
%proportion of False alarms, then returns the d' value.
%We assume that the mean is zero, and the S.D. is .5
%However, in the variables below, these parameters can be changed.
%Normalcy and Equal Variance are assumed here.
%Also, we return a -99 if any of the input values are 0 or 1.
%Reference: Equation 3.1 on page 68 of George A. Geshider's
%Psychophysics Method and Theory, 1976. Lawrence Earlbaum Associates,
Publishers.
%Distrbuted by the Halsted Press Division of John Wiley and Sons.
if proportionOfHits~=0 & proportionOfHits~=1 & proportionOfFAs~=0 &
proportionOfFAs~=1
%The d' calculation can be made since all values are between 0 and 1,
exclusive.
mean = 0; %Mean of the gaussian distribution on which the calc is
made.
stDev = .5; %StDeviation of the gaussian distribution on which the
calc is made.
zHits = norminv(proportionOfHits, mean, stDev);
zFalseAlarms = norminv(proportionOfFAs, mean, stDev);
d = zHits - zFalseAlarms;
else
d=-99; %The d' calculation cannot be made since at least one value
is a 0 or a 1.
%This is dummy value is returned just to avoid a divide=by-zero
error.
end
On 4/24/02 8:57 AM, "David Fass" <dfass@...> wrote:
>
> Hi. Can someone tell me whether the Psych Toolbox contains any functions
> for computing d-prime (the sensitivity measure)? Thanks.
>
> -- Dave
>
>
>
> ************************************
> David Fass dfass@...
> Visual Cognition Laboratory
> Rutgers Center for Cognitive Science
> http://ruccs.rutgers.edu/~dfass/
> ************************************
>
>
>
> http://psychtoolbox.org
> POST a message to: psychtoolbox@yahoogroups.com
> UNSUBSCRIBE by sending a blank message to:
> psychtoolbox-unsubscribe@yahoogroups.com
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>