ABO {VGAM}R Documentation

The ABO Blood Group System

Description

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

Usage

ABO(link = "logit", earg=list(), ir = NULL, ip = NULL)

Arguments

link Link function applied to p and q. See Links for more choices.
earg List. Extra argument applied to each of the links. See earg in Links for general information.
ir, ip Optional initial value for r and p. A NULL value means values are computed internally.

Details

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

Value

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

Note

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 weights argument is used to specify the total number of counts for each row.

Author(s)

T. W. Yee

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, AB.Ab.aB.ab2, G1G2G3, MNSs.

Examples

y = cbind(A=725, B=258, AB=72, O=1073) # Order matters, not the name
fit = vglm(y ~ 1, ABO(link=logit), trace=TRUE, cri="coef")
fit = vglm(y ~ 1, ABO(link=identity), trace=TRUE, cri="coef")
coef(fit, matrix=TRUE)
Coef(fit) # Estimated p and q
rbind(y, sum(y)*fitted(fit))
sqrt(diag(vcov(fit)))

[Package VGAM version 0.7-7 Index]