rrcov (version 1.7-2)

hemophilia: Hemophilia Data

Description

The hemophilia data set contains two measured variables on 75 women, belonging to two groups: n1=30 of them are non-carriers (normal group) and n2=45 are known hemophilia A carriers (obligatory carriers).

Usage

data(hemophilia)

Format

A data frame with 75 observations on the following 3 variables.

AHFactivity

AHF activity

AHFantigen

AHF antigen

gr

group - normal or obligatory carrier

Details

Originally analized in the context of discriminant analysis by Habemma and Hermans (1974). The objective is to find a procedure for detecting potential hemophilia A carriers on the basis of two measured variables: X1=log10(AHV activity) and X2=log10(AHV-like antigen). The first group of n1=30 women consists of known non-carriers (normal group) and the second group of n2=45 women is selected from known hemophilia A carriers (obligatory carriers). This data set was also analyzed by Johnson and Wichern (1998) as well as, in the context of robust Linear Discriminant Analysis by Hawkins and McLachlan (1997) and Hubert and Van Driessen (2004).

References

Johnson, R.A. and Wichern, D. W. Applied Multivariate Statistical Analysis (Prentice Hall, International Editions, 2002, fifth edition)

Hawkins, D. M. and McLachlan, G.J. (1997) High-Breakdown Linear Discriminant Analysis J. Amer. Statist. Assoc. 92 136--143.

Hubert, M., Van Driessen, K. (2004) Fast and robust discriminant analysis, Computational Statistics and Data Analysis, 45 301--320.

Examples

data(hemophilia)
plot(AHFantigen~AHFactivity, data=hemophilia, col=as.numeric(as.factor(gr))+1)
##
## Compute robust location and covariance matrix and 
## plot the tolerance ellipses
(mcd <- CovMcd(hemophilia[,1:2]))
col <- ifelse(hemophilia$gr == "carrier", 2, 3) ## define clours for the groups
plot(mcd, which="tolEllipsePlot", class=TRUE, col=col)