Relative frequencies of tag trigrams is selected Spanish texts
Relative frequencies of the 120 most frequent tag trigrams in 15 texts contributed by 3 authors.
data(spanish)
A data frame with 120 observations on 15 variables documented in
spanishMeta.
Spassova, M. S. (2006) Las marcas sintacticas de atribucion forense de autoria de textos escritos en espanol, Masters thesis, Institut Universitari de Linguistica Aplicada, Universitat Pompeu Fabra, Barcelona.
## Not run:
data(spanish)
data(spanishMeta)
# principal components analysis
spanish.t = t(spanish)
spanish.pca = prcomp(spanish.t, center = TRUE, scale = TRUE)
spanish.x = data.frame(spanish.pca$x)
spanish.x = spanish.x[order(rownames(spanish.x)), ]
library(lattice)
splom(~spanish.x[ , 1:3], groups = spanishMeta$Author)
# linear discriminant analysis
library(MASS)
spanish.pca.lda = lda(spanish.x[ , 1:8], spanishMeta$Author)
plot(spanish.pca.lda)
# cross-validation
n = 8
spanish.t = spanish.t[order(rownames(spanish.t)), ]
predictedClasses = rep("", 15)
for (i in 1:15) {
training = spanish.t[-i,]
trainingAuthor = spanishMeta[-i,]$Author
training.pca = prcomp(training, center=TRUE, scale=TRUE)
training.x = data.frame(training.pca$x)
training.x = training.x[order(rownames(training.x)), ]
training.pca.lda = lda(training[ , 1:n], trainingAuthor)
predictedClasses[i] =
as.character(predict(training.pca.lda, spanish.t[ , 1:n])$class[i])
}
ncorrect = sum(predictedClasses==as.character(spanishMeta$Author))
ncorrect
sum(dbinom(ncorrect:15, 15, 1/3))
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