Package edu.cmu.tetrad.search

Class DeltaTetradTest

java.lang.Object
edu.cmu.tetrad.search.DeltaTetradTest
public class DeltaTetradTest extends Object
Implements a test for simultaneously zero tetrads in Bollen, K. (1990). "Outlier screening and distribution-free test for vanishing tetrads." Sociological Methods and Research 19, 80-92 and Bollen and Ting, Confirmatory Tetrad Analysis.
Author:
Joseph Ramsey

  • Constructor Details

    • DeltaTetradTest

      public DeltaTetradTest(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.

    • DeltaTetradTest

      public DeltaTetradTest(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.

  • Method Details

    • calcChiSquare

      public double calcChiSquare(Tetrad... tetrads)
      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.

    • getPValue

      public double getPValue()
      Returns:
      the p value for the most recent test.

    • getPValue

      public double getPValue(Tetrad... tetrads)