Title: good job, but not yet done
1. Overall Impression: This package is useful and has fewer bugs than might be expected in a 0.x version.
2. The sigmasq method does not work. Here's the error message that I got when I tried to use it:
Internal Error: yelement is undef at C:/Perl/site/lib/Statistics/Regression.pm line 265.
3. For the sake of efficiency, there should be a mechanism for adding multiple observations at a single shot.
4. The documentation should specify the formulas that are being used or at least provide references.
5. It would be nice to have a method that returns the coefficients, R^2, and sigma^2 all at a single shot (returning a reference to the coefficient vector).
The generator has excellent properties, and the newly-added ability to initialize with an array of integers means that one can have a virtually unlimited number of random number streams. The documentation is also greatly improved from the previous release.