# A1A2A3: The A1A2A3 Blood Group System In VGAM: Vector Generalized Linear and Additive Models

 A1A2A3 R Documentation

## The A1A2A3 Blood Group System

### Description

Estimates the three independent parameters of the the A1A2A3 blood group system.

### Usage

```A1A2A3(link = "logitlink", inbreeding = FALSE, ip1 = NULL, ip2 = NULL, iF = NULL)
```

### Arguments

 `link` Link function applied to `p1`, `p2` and `f`. See `Links` for more choices. `inbreeding` Logical. Is there inbreeding? `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 if `inbreeding = TRUE`. If `inbreeding = FALSE` then f = 0 and Hardy-Weinberg Equilibrium (HWE) is assumed.

### 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 `A1A1`, `A1A2`, `A1A3`, `A2A2`, `A2A3`, `A3A3` (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

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

`AA.Aa.aa`, `AB.Ab.aB.ab`, `ABO`, `MNSs`.

### Examples

```ymat <- cbind(108, 196, 429, 143, 513, 559)
fit <- vglm(ymat ~ 1, A1A2A3(link = probitlink), trace = TRUE, crit = "coef")
fit <- vglm(ymat ~ 1, A1A2A3(link = logitlink, ip1 = 0.3, ip2 = 0.3, iF = 0.02),
trace = TRUE, crit = "coef")
Coef(fit)  # Estimated p1 and p2
rbind(ymat, sum(ymat) * fitted(fit))
sqrt(diag(vcov(fit)))
```

VGAM documentation built on July 6, 2022, 5:05 p.m.