signal {statpsych} | R Documentation |
Parameter estimates for a signal detection study
Description
Computes the hit rate, false alarm rate, d-prime, threshold, and bias for one participant (observer) in a Yes/No signal detection study. An equal-variance Gausian model is assumed. The parameter estimates are computed after adding .5 to the number of "Yes" responses in each condtion (the signal and noise conditions) and adding 1 to the number of signal trials and to the number of noise trails. In memory recognition studies, the observers is first presented with set of words or images to study, and is later presented with another set of words or images where some items are from the first list (old items) and some items are new items.
Usage
signal(f1, f2, n1, n2)
Arguments
f1 |
number of "Yes" responses in the stimulus (old item) trials |
f2 |
number of "Yes" responses in the noise (new item) trials |
n1 |
number of stimulus (or old item) trials |
n2 |
number of noise (or new item) trials |
Value
Returns a 1-row matrix. The columns are:
HR - estimate of hit rate
FAR - estimate of false alarm rate
d-prime - estimate of d-prime
Threshold - estimate of threshold (criterion)
Bias - estimate of threshold minus d-prime/2
References
Wickens TD (2002). Elementary Signal Detection Theory. Oxford.
Examples
signal(82, 46, 100, 100)
# Should return:
# HR FAR d-prime Threshold Bias
# 0.8168317 0.460396 1.002793 0.09943603 -0.4019603