Update data science solution

This again is totally pegged to the sample data. If I change a single line in the `sample_data.json` file, your test fails, even though the class works properly. 

Also, why use `.to_i` on the samples? Don't you expect them to be a Fixnum already?

Try considering it this way. If you look at the verbose rspec output, it should say something like: "ABDataParser with valid arguments has 1349 samples for variant A". Is that statement always true? Or is there something else you want to get at with the test.