The use of FLAG_IMPLICIT_SIGNIFICANCE is in experimental state. flag_implicit_significance might even become obsolete. FLAG_IMPLICIT_SIGNIFICANCE sets and gets default alpha (level) of any significance test The default alpha-level is stored in the global variable FLAG_implicit_significance The idea is that the significance must not be assigned explicitely. This might yield more readable code. Choose alpha low enough, because in alpha*100% of the cases, you will reject the Null hypothesis just by change. For this reason, the default alpha is 0.01. flag_implicit_significance(0.01) sets the alpha-level for the significance test alpha = flag_implicit_significance() gets default alpha flag_implicit_significance(alpha) sets default alpha-level alpha = flag_implicit_significance(alpha) gets and sets alpha features: - compatible to Matlab and Octave see also: CORRCOEF, PARTCORRCOEF