ngfinder {mrt}R Documentation

Nominal group finder (Kelley & Wright, 2010, BRM)

Description

Finds the set of nominal groups which is representative of all possible sets for either mean, variance (and other moments) or the distribution. Details are in Kelley and Wright (2010), where a C++ function also described.

Usage

ngfinder(nomg, number = 2, right = 1, replic = 1000, moments = NULL, distmeth = "ks", ...)

Arguments

nomg The data file. One line per participant
number The size of the groups
right The value for a correct answer
replic How many samples to draw
moments If matching on moments, how many to use. 2 is recommended
distmeth If matching on distributions, whether to use Kolmogorov-Smirnov or Pearson method
... Other arguments

Details

The function takes a data matrix for a control condition in a collaboration study, and finds a set which is really close to the average of all possible sets. Details are in Kelley and Wright (2010), which is an advance on Wright (2007).

Value

forgroups The numbers for the optimal groups, so the participant numbers
values The number of correct responses for each of the groups

Author(s)

Daniel B. Wright, dwright@fiu.edu

References

Kelley, M. R. & Wright, D.B. (2010) Obtaining representative nominal groups. Behavior Research Methods.
Wright, D.B. (2007). Calculating nominal group statistics in collaboration studies. Behavior Research Methods, 39, 460-470.

Examples

set.seed(32)
dmat <- rbinom(120,1,.4)
dim(dmat) <- c(12,10)
ngfinder(dmat,number=3,replic=4)
ngfinder(dmat,number=3,replic=4,moments=3)

[Package mrt version 0.3 Index]