Foreword by Brian C.J. MoorePreface1 WHA T ARE STATISTICA L DECISIONS ? 1An example 1Some definitions 3Decision rules and the criterion 6Signal detection theory and psychology 102 NON-PARAMETRI C MEASURE S OF SENSITIVIT Y 18The yes-no task 18The rating scale task 25Area estimation with only a single pair of hit and falsealarm rates 31The forced-choice task 40An overall view of non-parametric sensitivity measures 453 GAUSSIA N DISTRIBUTION S O F SIGNA L AN DNOIS E WIT H EQUA L VARIANCE S 5 0The ROC curve for the yes-no task 50Double-probability scales 53The formula for d 57The criterion 58Forced-choice tasks 644 GAUSSIA N DISTRIBUTION S OF SIGNA L ANDNOIS E WIT H UNEQUA L VARIANCE S 7 9ROC curves for unequal variance cases 80Sensitivity measures in the unequal variance case 86Measuring the signal distribution variance 91The measurement of response bias 925 CONDUCTIN G A RATIN G SCALE EXPERIMEN T 99Experimental design 100CONTENTSAnalysis of data 105Measures of sensitivity 113Measures of bias 1196 CHOICE THEORY APPROXIMATION S TOSIGNA L DETECTIO N THEOR Y 13 1The logistic distribution 134Determining detection measures from logistic distributions 136The matrix of relative response strengths 139Open-ended tasks 141A summary of the procedure for an open-ended task 1477 THRESHOL D THEOR Y 157Classical psychophysics 157High threshold theory and the yes-no task 162Forced-choice tasks 172Other evidence favouring detection theory 1808 THE LAW S OF CATEGORICA L ANDCOMPARATIV E JUDGEMEN T 18 5Antecedents of signal detection theory 185Category rating tasks 186Forced-choice tasks and the Law of ComparativeJudgement 206Bibliography 215Appendix 1 Answers to problems 219Appendix 2 Logarithms 223Appendix 3 Integration of the expression for the logistic curve 225Appendix 4 Tables 227Index 237