R: Calculation of beta scaling parameters

b.scal {klaR} | R Documentation

## Calculation of beta scaling parameters

### Description

Calculates the scaling parameter for `betascale`.

### Usage

    b.scal(member, grouping, dis = FALSE, eps = 1e-04)

### Arguments

`member` | Membership values of an argmax classification method. Eg. posterior probabilities of `lda`. Row-wise values must sum up to 1 and must be in the interval [0,1].
`grouping` | Class vector.
`dis` | Logical, whether to optimize the dispersion parameter in `pbeta`.
`eps` | Minimum variation of membership values. If variance is smaller than `eps`, the values are treated as one point.

### Details

With `betascale` and `b.scal`, membership values of an argmax classifier are scaled in such a way, that the mean membership value of those values which are assigned to each class reflect the mean correctness rate of that values. This is done via `qbeta` and `pbeta` with the appropriate shape parameters. If `dis` is `TRUE`, it is tried that the variation of membership values is optimal for the accuracy relative to the correctness rate. If the variation of the membership values is less than `eps`, they are treated as one point and shifted towards the correctness rate.

### Value

A list containing

`model` | Estimated parameters for `betascale`.
`eps` | Value of `eps` from the call.
`member` | Scaled membership values.

### Author(s)

Karsten Luebke (karsten.luebke@fom.de), Uwe Ligges

### References

Garczarek, Ursula Maria (2002): Classification rules in standardized partition spaces. Dissertation, University of Dortmund. URL http://hdl.handle.net/2003/2789

### See Also

`betascale`, `e.scal`

### Examples

    library(MASS)
    data(B3)
    pB3 <- predict(lda(PHASEN ~ ., data = B3))$posterior
    pbB3 <- b.scal(pB3, B3$PHASEN, dis = TRUE)
    ucpm(pB3, B3$PHASEN)
    ucpm(pbB3$member, B3$PHASEN)

[Package klaR version 0.6-12 Index]