dprime.mAFC | R Documentation |
Calculate the value of d'
for an m-alternative forced choice paradigm
dprime.mAFC(Pc, m)
Pc |
The proportion of correct responses based on either the Hit rate or based on an unbiased observer |
m |
The number of alternative choices, an integer > 1. |
The probability of a correct response in m-alternative forced-choice, assuming independence, is based on the product of the likelihoods of the signal alternative generating the strongest response and the m - 1 noise alternatives generating responses less than this value (Green and Dai, 1991). For a Yes-No paradigm, the sensitivity is calculated more simply as
d' = \code{qnorm}(H) - \code{qnorm}(F)
where H
and F
are the Hit and False Alarm rates,
respectively.
Returns the value of d'
Currently is only valid for d'
in the interval [-10, 10]
which should be well outside the range of sensory differences that
this paradigm is used to investigate.
Kenneth Knoblauch
Green, D. M. and Dai, H. (1991) Probability of being correct with 1 of M orthogonal signals. Perception & Psychophysics, 49, 100–101.
Green, D. M. and Swets, J. A. (1966) Signal Detection Theory and Psychophysics Robert E. Krieger Publishing Company
See Also dprime.ABX
, dprime.SD
,
dprime.oddity
dprime.mAFC(0.8, 4)
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