threshold_slope: Threshold and slope of estimated psychometric function

In modelfree: Model-free estimation of a psychometric function

Description

Finds the approximate value of x (=x_th) for which the value of the psychometric function is equal thresh and the approximate value of slope in x_th

Usage

threshold_slope( pfit, xfit, thresh = 0.5 )

Arguments

pfit	estimated values of the psychometric function
xfit	stimulus levels in which the function was estimated
thresh	value for which to estimate threshold; default is 0.5

Value

value

Object with 2 elements: x_th: estimated threshold slope: estimated value of slope, i.e. derivative of pfit at x_th

Examples

data( "01_Miranda" )
xnew = 1.2 * (0:999)/999+0.1
h = 0.2959
fit <- locglmfit( xnew, example01$r, example01$m, example01$x, h )
value <- threshold_slope( fit$pfit , xnew )

Example output

Loading required package: PolynomF
Loading required package: SparseM

Attaching package: 'SparseM'

The following object is masked from 'package:base':

    backsolve

modelfree documentation built on May 2, 2019, 6:07 p.m.