| c5ml {lazy.mdpref} | R Documentation |
ML Solution to Thurstone Case V of Paired Comparison Data with logistic probability
c5ml(f, n, ij, sname = NULL, minp = 1e-09, lmax = 50, eps = 1e-06, print = 1)
f |
vector of # of times that the left object was preferred. |
n |
vector of # of trials per pair or scalar . |
ij |
matrix indicating the stimulus pair: i, j. When sname is NULL the elements of ij will be used as the names. |
minp |
minimum value of probability when n=1. |
lmax |
max # of iterations. |
eps |
criterion for convergence. |
print |
= 1 to print result. |
f_ij is the # of times that sutimulus i is preferred over stimulus j
out of n_ij comparisons.
f_ij is assumed to have binomial distribution win n_ij and p_ij
where p_ij = logistic( x_i - x_j ).
set.seed(1701)
x <- c(-.5,0,1)
ij <- matrix(c(2,1, 3,1, 3,2), 3,2, byrow=1)
ijc <- t( apply(4-ij,1, function(x) paste("s",x,sep="")) )
z <- c(x[2]-x[1], x[3]-x[1], x[3]-x[2])
p <- logistic(z)
n <- c(10,10,10)
f <- mapply( function(size,prob){ rbinom(1,size,prob) }, n, p )
res2 <- c5ml( f, n, ij )
res1 <- c5ml( f, n, ijc, sname=c("s33","s22","s11") )