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DiscriMiner (version 0.1-22)

quaDA: Quadratic Discriminant Analysis

Description

Performs a Quadratic Discriminant Analysis

Usage

quaDA(variables, group, prior = NULL, validation = NULL, learn = NULL, test = NULL, prob = FALSE)

Arguments

variables
matrix or data frame with explanatory variables
group
vector or factor with group memberships
prior
optional vector of prior probabilities. Default prior=NULL implies group proportions
validation
type of validation, either "crossval" or "learntest". Default NULL
learn
optional vector of indices for a learn-set. Only used when validation="learntest". Default NULL
test
optional vector of indices for a test-set. Only used when validation="learntest". Default NULL
prob
logical indicating whether the group classification results should be expressed in probability terms

Value

  • An object of class "quada", basically a list with the following elements
  • confusionconfusion matrix
  • scoresdiscriminant scores for each observation
  • classificationassigned class
  • error_ratemisclassification error rate

Details

When validation=NULL there is no validation When validation="crossval" cross-validation is performed by randomly separating the observations in ten groups. When validation="learntest" validationi is performed by providing a learn-set and a test-set of observations.

References

Lebart L., Piron M., Morineau A. (2006) Statistique Exploratoire Multidimensionnelle. Dunod, Paris.

Tenenhaus G. (2007) Statistique. Dunod, Paris. Tuffery S. (2011) Data Mining and Statistics for Decision Making. Wiley, Chichester.

See Also

classify, desDA, geoDA, linDA, plsDA

Examples

Run this code
# load iris dataset
  data(iris)

  # quadratic discriminant analysis with no validation
  my_qua1 = quaDA(iris[,1:4], iris$Species)
  my_qua1$confusion
  my_qua1$error_rate

  # quadratic discriminant analysis with cross-validation
  my_qua2 = quaDA(iris[,1:4], iris$Species, validation="crossval")
  my_qua2$confusion
  my_qua2$error_rate
  
  # quadratic discriminant analysis with learn-test validation
  learning = c(1:40, 51:90, 101:140)
  testing = c(41:50, 91:100, 141:150)
  my_qua3 = quaDA(iris[,1:4], iris$Species, validation="learntest", learn=learning, test=testing)
  my_qua3$confusion
  my_qua3$error_rate

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