AB.Ab.aB.ab {VGAM}

The AB-Ab-aB-ab Blood Group System

Description

Estimates the parameter of the AB-Ab-aB-ab blood group system.

Usage

AB.Ab.aB.ab(link = "logitlink", init.p = NULL)

Arguments

link

Link function applied to p. See Links for more choices.

init.p

Optional initial value for p.

Details

This one parameter model involves a probability called p.

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 AB, Ab, aB and ab (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, ABO, A1A2A3, MNSs.

Examples

ymat <- cbind(AB=1997, Ab=906, aB=904, ab=32)  # Data from Fisher (1925)
fit <- vglm(ymat ~ 1, AB.Ab.aB.ab(link = "identitylink"), trace = TRUE)
fit <- vglm(ymat ~ 1, AB.Ab.aB.ab, trace = TRUE)
rbind(ymat, sum(ymat)*fitted(fit))
Coef(fit)  # Estimated p
p <- sqrt(4*(fitted(fit)[, 4]))
p*p
summary(fit)