The law of large numbers states that as the sample grows in size the percentage of numbers falling within the standard deviation of the sample nears 68.2%

Problem is, the description is talking about the sample standard deviation, while the kata expects population standard deviation, which are different things.

That will be great thanks very much for the offer! I've made it available to contributors.

Nice kata :) Random tests needed. If you would need some help I'm always glad to help out.

Looks good! :)

Thanks dcsmith for pointing that out for me! Hopefully it's better now.

The tests are using Test.expect(bool, msg) which simply expects bool to be truthy, which allows my solution to pass ;)

You want to change it to Test.assertEquals(actual, expected, msg)