pairwise (version 0.1.5)

ptbis.dicho: Point Biserial Correlations dichotomous 1PL

Description

Calculation of the point biserial correlations for dichotomous item categories with total scale parameter (person parameter).

Usage

ptbis.dicho(daten, scale)

Arguments

daten

a data matrix, potentially with missing values, comprising dichotomous items (columns).

scale

an integer vector as an result of any scaling approach (WLE, MLE, Rawscore, etc. ) relating to the Items (columns) in daten.

Value

• An object of class "list" and "itanaldicho" containing item statistics.

Details

no details in the moment.

Examples

######################
##### compute person ML estimates first ########
data(cog);data(cogBOOKLET) # loading reponse and allocation data
d<-(cog[cog$BOOKID!=14,]) # skip persons which got booklet No.14.
inc<-make.incidenz(tab=cogBOOKLET, bookid=d$BOOKID) # make just the incidenz matrix
result<-ppML.dicho(daten=d[,4:34], SIGMA=itempar.dicho(d[,4:34]),incidenz = inc )
MLscale<-summary(result,FALSE)[,1] # return just the ML person estimates and their standard errors.
##### now compute item statistics ########
ptbis.dicho(daten=d[,4:34], scale=MLscale)