A FORTRAN PROGRAM, 'SIGMPLOT', FOR FITTING SIGMOID CURVES TO THRESHOLD DATA AND FOR PLOTTING THE RESULT

A computer program is presented for determining position andslope of a symmetrical sigmoid curve which fits to experimentaldata obtained in experiments with absolute or discriminationthresholds. If a suitable plotter is available, the programprovides a plotting of experimental data and the fitted curve.50 % and 75 % threshold values and the difference between these(in certain cases equal to the ‘jnd’) are alwaysprinted. Available options and necessary limitations are described.