itemtable: Summary of DIF items

In pwrRasch: Statistical Power Simulation for Testing the Rasch Model

Description

This function builds a table of DIF items specified in the pwrrasch object

Usage

itemtable(object, all = FALSE, digits = 2)

Arguments

object	pwrrasch object
all	If TRUE, all items are included in the table.
digits	Integer indicating the number of decimal places.

Author(s)

Takuya Yanagida [e-mail], Jan Steinfeld [e-mail]

Examples

## Not run: 

# item parameters
ipar2 <- ipar1 <- seq(-3, 3, length.out = 20)
# model differential item function (DIF)
ipar2[10] <- ipar1[11]
ipar2[11] <- ipar1[10]
# simulation for b = 100
simres <- pwr.rasch(100, ipar = list(ipar1, ipar2))
itemtable(simres)

## End(Not run)

Example output

|----------------------------------------------------------|
| pwrRasch 0.1-2 (2015-09-28)                              |
| Statistical Power Simulation for Testing the Rasch Model |
|----------------------------------------------------------|
--------------------------------------------------------
  Call:    pwr.rasch(b = 100, ipar = list(ipar1, ipar2))
  Time:    2018-12-21 03:33:55 
  R:       R version 3.4.4 (2018-03-15) 
  Package: pwrRasch version 0.1-2 (2015-09-28) 
--------------------------------------------------------
  Conducting H0 simulation...    2018-12-21 03:33:55
  Conducting H1 simulation...    2018-12-21 03:33:56
  Finished simulation...         2018-12-21 03:33:56
--------------------------------------------------------
Time difference of 1.7 secs

  Statistical Power Simulation for the Rasch model 

     b (number of persons in each group):  100 
     c (number of items):                  20 
     simulation runs:                      1000 

     Estimated statistical power:  0.104 
     Nominal significance level:   0.05 
     Empirical significance level: 0.054 
--------------------------------------------------------

Summary of DIF items specified in the pwrrasch object

   item parameters:  [-3, 3]
   n items:          20 
   n DIF items:      2 

      Pos10 Pos11 SUM
ipar1 -0.16  0.16 0.0
ipar2  0.16 -0.16 0.0
DIF    0.32  0.32 0.6

pwrRasch documentation built on May 1, 2019, 10:37 p.m.