Psychometric functions resulting from power-function transducers and zero pedestal.

<p>The thin, coloured curves show the psychometric function of <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0074815#pone.0074815.e395" target="_blank">Equation (65</a>), plotted as a function of . Different rows of panels show psychometric functions with different noise CDFs, <i>F</i>, given by the Laplace distribution (top row of panels), the Gaussian (second row), the generalized Gaussian with (third row) or logistic (bottom row). Different columns of panels show psychometric functions for different transducer exponents, <i>b</i>, as indicated at the top of the figure. The thick, black curves show the best-fitting (maximum-likelihood) Weibull functions. The curves in the middle column (, top to bottom) are identical to <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0074815#pone-0074815-g007" target="_blank">Figures 7A to 7D</a>, respectively. This is because gives a linear transducer, and so the psychometric functions for will have the same shape and same fitted <i>β</i> as the CDF (see Equation (10)). Each panel displays the <i>β</i> value of the best-fitting Weibull function () and the estimate, , where is given by <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0074815#pone.0074815.e309" target="_blank">Equation (52</a>), (53), (54) or (60), as appropriate.