VGAM (version 1.0-1)

ABO: The ABO Blood Group System

Description

Estimates the two independent parameters of the the ABO blood group system.

Usage

ABO(link.pA = "logit", link.pB = "logit", ipA = NULL, ipB = NULL,
    ipO = NULL, zero = NULL)

Arguments

link.pA, link.pB

Link functions applied to pA and pB. See Links for more choices.

ipA, ipB, ipO

Optional initial value for pA and pB and pO. A NULL value means values are computed internally.

zero

Details at CommonVGAMffArguments.

Value

• An object of class "vglmff" (see vglmff-class). The object is used by modelling functions such as vglm and vgam.

Details

The parameters pA and pB are probabilities, so that pO=1-pA-pB is the third probability. The probabilities pA and pB correspond to A and B respectively, so that pO is the probability for O. It is easier to make use of initial values for pO than for pB. In documentation elsewhere I sometimes use pA=p, pB=q, pO=r.

References

Lange, K. (2002) Mathematical and Statistical Methods for Genetic Analysis, 2nd ed. New York: Springer-Verlag.

See Also

AA.Aa.aa, AB.Ab.aB.ab, A1A2A3, MNSs.

Examples

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, cri = "coef")
coef(fit, matrix = TRUE)
Coef(fit)  # Estimated pA and pB
rbind(ymat, sum(ymat) * fitted(fit))
sqrt(diag(vcov(fit)))