modelfree (version 1.0-2)

threshold_slope: Threshold and slope of estimated 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 )