G1G2G3 {VGAM} | R Documentation

## The G1G2G3 Blood Group System

### Description

Estimates the three independent parameters of the the G1G2G3 blood group system.

### Usage

    G1G2G3(link = "logit", earg=list(), ip1 = NULL, ip2 = NULL, iF = NULL)

### Arguments

`link` | Link function applied to `p1`, `p2` and `f`. See `Links` for more choices.
`earg` | List. Extra argument for the link. See `earg` in `Links` for general information.
`ip1, ip2, iF` | Optional initial value for `p1`, `p2` and `f`.

### Details

The parameters `p1` and `p2` are probabilities, so that `p3=1-p1-p2` is the third probability. The parameter `f` is the third independent parameter.

### 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 6-column matrix of counts, with columns corresponding to `G1G1`, `G1G2`, `G1G3`, `G2G2`, `G2G3`, `G3G3` (in order). Alternatively, the input can be a 6-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`, `ABO`, `MNSs`.

### Examples

    y = cbind(108, 196, 429, 143, 513, 559)
    fit = vglm(y ~ 1, G1G2G3(link=probit), trace=TRUE, crit="coef")
    fit = vglm(y ~ 1, G1G2G3(link=logit, ip1=.3, ip2=.3, iF=.02),
               trace=TRUE, crit="coef")
    fit = vglm(y ~ 1, G1G2G3(link="identity"), trace=TRUE)
    Coef(fit) # Estimated p1, p2 and f
    rbind(y, sum(y)*fitted(fit))
    sqrt(diag(vcov(fit)))

[Package VGAM version 0.7-9 Index]