From: Ken Knoblauch <knoblauch_at_lyon.inserm.fr>

Date: Thu 10 Mar 2005 - 03:27:27 EST

language R

Ken Knoblauch

Inserm U 371

Cerveau et Vision

18 avenue du Doyen Lepine

69675 Bron cedex

France

tel: +33 (0)4 72 91 34 77

fax: +33 (0)4 72 91 34 61

portable: 06 84 10 64 10

R-help@stat.math.ethz.ch mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Thu Mar 10 04:48:03 2005

Date: Thu 10 Mar 2005 - 03:27:27 EST

Hi,

I'm trying to calculate the value of the variable, dp, below, in the argument to the integral of dnorm(x-dp) * pnorm(x)^(m-1). This corresponds to the estimate of the sensitivity of an observer in an m-alternative forced choice experiment, given the probability of a correct response, Pc, a Gaussian assumption for the noise and no bias. The function that I wrote below gives me an error:

Error in f(x, ...) : recursive default argument reference

dprime.mAFC <- function(Pc, m) {

est.dp <- function(dp, Pc = Pc, m = m) {

pr <- function(x, dpt = dp, m0 = m) { dnorm(x - dpt) * pnorm(x)^(m0 - 1) } Pc - integrate(pr, lower = -Inf, upper = Inf, dpt = dp, m0 = m)$value } dp.res <- uniroot(est.dp, interval = c(0,5), Pc = Pc, m = m) dp.res$root } platform powerpc-apple-darwin6.8 arch powerpc os darwin6.8 system powerpc, darwin6.8 status major 2 minor 0.1 year 2004 month 11 day 15

language R

ken

Ken Knoblauch

Inserm U 371

Cerveau et Vision

18 avenue du Doyen Lepine

69675 Bron cedex

France

tel: +33 (0)4 72 91 34 77

fax: +33 (0)4 72 91 34 61

portable: 06 84 10 64 10

R-help@stat.math.ethz.ch mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Thu Mar 10 04:48:03 2005

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