Given a matrix of product-moment correlation coefficients computed on 'closed data' (a system of percentage variables), the test of departure from zero correlation is clearly inappropriate because closure of data imposes non-zero correlation.Subroutine CHAYES estimates 'Null Correlations' and calculates a t-matrix which may be used to test the hypothesis that observed product-moment correlations are due to the closure property. The calculated t-matrix is at best an approximation. This is found in certain mathematical assumptions leading to this t-test, and the recognition that statistical assumptions in the theory of t-testing are not satisfied. Great care must be exercized in accepting or rejecting correlations by this test. Therefore, results of the t-test are no substitute for sound geological reasoning, caveat emptor.
Evaluating Patent Ductus Arteriosus during Percutaneous Closure: Correlation between Intravascular Ultrasonography and Computed Tomographic Angiography