madlib/madlib — pull request #164 by fschopp (2012-06-04 19:35:13+00:00)
Title: Hypothesis tests: Fixes for MADLIB-526, MADLIB-527, MADLIB-528

- Welch–Satterthwaite formula gives non-integrate degress of freedom, but documentation used to say that an integral value is returned.
- Since the MW test is a rank-based test, there is no reason to disallow infinities. NaNs on the other hand now propagate. No error is raised.
- §4.15.4 ("Aggregate functions") of ISO/IEC 9075-2:2003, "SQL/Foundation" demands that aggregate functions ignore rows with NULL values. It is therefore confusing to use NULL arguments. The chi-squared GOF now has numeric default values for the expected number of observations (1) and degree of freedom (0), and the documentation explains how these values are interpreted.