DataMuseum.dk

top - download

    Length: 2108 (0x83c)
    Types: TextFile
    Names: »dprime.man«

└─⟦a0efdde77⟧ Bits:30001252 EUUGD11 Tape, 1987 Spring Conference Helsinki
    └─ ⟦this⟧ »EUUGD11/stat-5.3/eu/stat/doc/dprime.man« 

TextFile

DPRIME(1)                          |STAT                       October 1985

NAME
     dprime - compute d' and beta for signal detection data

SYNOPSIS
     dprime [hit-rate false-alarm-rate]

DESCRIPTION
     _▶08◀d_▶08◀p_▶08◀r_▶08◀i_▶08◀m_▶08◀e can be given two arguments: the hit-rate and the false-alarm-
     rate, for which it will print d' and beta.  Otherwise, _▶08◀d_▶08◀p_▶08◀r_▶08◀i_▶08◀m_▶08◀e reads
     raw data from the standard input.  If raw data are input, _▶08◀d_▶08◀p_▶08◀r_▶08◀i_▶08◀m_▶08◀e
     assumes a two column input in which the first column tells whether
     signal+noise or just noise were presented, and the second column tells
     how the observer responded.  The following strings can be used to
     indicate affirmative answers
                                 signal, yes, 1
     while the following can be used to indicate negative:
                                  noise, no, 0
     Upper case forms for the above are allowed.

ALGORITHM
     The value for d' is the Z value of the hit-rate minus that of the
     false-alarm-rate.
                              d' = Z(hr) - Z(far)
     This reflects the distance between the two distributions: signal, and
     signal+noise.  Though Z values can have any real value, normally
     distributed ones are between -2 and 2 about 95% of the time, so
     differences of twice that would be rare.

     The value for beta is the ratio of the normal density functions of the
     Z values used in the computation of d'.  This reflects an observer's
     bias to say `yes' or `no' with the unbiased observer having a value
     around 1.0.  A major reason for doing a signal detection analysis is
     to get a measure of discrimination that is constant over observer
     biases, but the invariance of beta is often not certain.

EXAMPLE
     dprime .7 .4     # will print
     hr     far    dprime beta
     0.70   0.40   0.78   0.90

REFERENCE
     The chapter on Theory of Signal Detection in Coombs, Dawes, and
     Tversky's _▶08◀M_▶08◀a_▶08◀t_▶08◀h_▶08◀e_▶08◀m_▶08◀a_▶08◀t_▶08◀i_▶08◀c_▶08◀a_▶08◀l _▶08◀P_▶08◀s_▶08◀y_▶08◀c_▶08◀h_▶08◀o_▶08◀l_▶08◀o_▶08◀g_▶08◀y, 1970, Academic Press.

BUGS
     The program has not been tested extensively.