# MNSs: The MNSs Blood Group System In VGAM: Vector Generalized Linear and Additive Models

## Description

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

## Usage

 `1` ```MNSs(link = "logitlink", imS = NULL, ims = NULL, inS = NULL) ```

## Arguments

 `link` Link function applied to the three parameters. See `Links` for more choices. `imS, ims, inS` Optional initial value for `mS`, `ms` and `nS` respectively. A `NULL` means they are computed internally.

## Details

There are three independent parameters: `m_S`, `m_s`, `n_S`, say, so that `n_s = 1 - m_S - m_s - n_S`. We let the eta vector (transposed) be `(g(m_S), g(m_s), g(n_S))` where `g` is the link function.

## 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, where the columns are MS, Ms, MNS, MNs, NS, Ns (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.

T. W. Yee

## References

Elandt-Johnson, R. C. (1971). Probability Models and Statistical Methods in Genetics, New York: Wiley.

`AA.Aa.aa`, `AB.Ab.aB.ab`, `ABO`, `A1A2A3`.
 ```1 2 3 4 5 6 7``` ```# Order matters only: y <- cbind(MS = 295, Ms = 107, MNS = 379, MNs = 322, NS = 102, Ns = 214) fit <- vglm(y ~ 1, MNSs("logitlink", .25, .28, .08), trace = TRUE) fit <- vglm(y ~ 1, MNSs(link = logitlink), trace = TRUE, crit = "coef") Coef(fit) rbind(y, sum(y)*fitted(fit)) sqrt(diag(vcov(fit))) ```