I’ve just released daru (Data Analysis in RUby -
https://github.com/v0dro/daru), a comprehensive data analysis,
manipulation and plotting library for ruby.
It is now completely compatible with statsample
(https://github.com/SciRuby/statsample) and can thus can perform many
varied statistical computations and even plot them pretty.
You can see a preview of the API yourself in the notebooks section
Do check it out and give it a shot! Any feedback is welcome