Class DeltaSextadTest

java.lang.Object
edu.cmu.tetrad.search.utils.DeltaSextadTest

public class DeltaSextadTest extends Object
Implements a test for simultaneously zero sextads in the style of Bollen, K. (1990). Sociological Methods and Research 19, 80-92 and Bollen and Ting, Confirmatory Tetrad Analysis.
Author:
josephramsey
  • Constructor Details

    • DeltaSextadTest

      public DeltaSextadTest(DataSet dataSet)
      Constructs a test using a given data set. If a data set is provided (that is, a tabular data set), fourth moment statistics can be calculated (p. 160); otherwise, it must be assumed that the data are multivariate Gaussian.
      Parameters:
      dataSet - The dataset to use.
    • DeltaSextadTest

      public DeltaSextadTest(ICovarianceMatrix cov)
      Constructs a test using the given covariance matrix. Fourth moment statistics are not caculated; it is assumed that the data are distributed as multivariate Gaussian.
      Parameters:
      cov - The covariance matrix to use.
  • Method Details

    • serializableInstance

      public static DeltaSextadTest serializableInstance()
      Generates a simple exemplar of this class to test serialization.
      Returns:
      This instance.
    • getPValue

      public double getPValue(Sextad... sextads)
      Takes a list of tetrads for the given data set and returns the chi square value for the test. We assume that the tetrads are non-redundant; if not, a matrix exception will be thrown.

      Calculates the T statistic (Bollen and Ting, p. 161). This is significant if tests as significant using the Chi Square distribution with degrees of freedom equal to the number of nonredundant tetrads tested.

      Parameters:
      sextads - The sextads for which a p-value is needed.
      Returns:
      The p-value.
    • calcChiSquare

      public double calcChiSquare(Sextad[] sextads)
      Takes a list of tetrads for the given data set and returns the chi square value for the test. We assume that the tetrads are non-redundant; if not, a matrix exception will be thrown.

      Calculates the T statistic (Bollen and Ting, p. 161). This is significant if tests as significant using the Chi Square distribution with degrees of freedom equal to the number of nonredundant tetrads tested.

      Parameters:
      sextads - The sextads for which a chi-square is needed
      Returns:
      The chi-square.
    • getVariables

      public List<Node> getVariables()
      Returns the variables of the data being used.
      Returns:
      This list.