Estimates the two independent parameters of the the ABO blood group system.
ABO(link.pA = "logitlink", link.pB = "logitlink", ipA = NULL, ipB = NULL, ipO = NULL, zero = NULL)
Link functions applied to
Optional initial value for
pB are probabilities, so that
pO=1-pA-pB is the third probability.
pB correspond to A and B respectively,
pO is the probability for O.
It is easier to make use of initial values for
pO than for
In documentation elsewhere I sometimes use
An object of class
The object is used by modelling functions such as
The input can be a 4-column matrix of counts, where the columns
are A, B, AB, O (in order).
Alternatively, the input can be a 4-column matrix of
proportions (so each row adds to 1) and the
argument is used to specify the total number of counts for each row.
T. W. Yee
Lange, K. (2002). Mathematical and Statistical Methods for Genetic Analysis, 2nd ed. New York: Springer-Verlag.
ymat <- cbind(A = 725, B = 258, AB = 72, O = 1073) # Order matters, not the name fit <- vglm(ymat ~ 1, ABO(link.pA = "identitylink", link.pB = "identitylink"), trace = TRUE, crit = "coef") coef(fit, matrix = TRUE) Coef(fit) # Estimated pA and pB rbind(ymat, sum(ymat) * fitted(fit)) sqrt(diag(vcov(fit)))
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