Khan/khan-exercises — pull request #81499 by bsimonse (2013-09-26 01:51:06+00:00)
Title: Confidence interval exercise

This is a new exercise for the first Confidence Interval video
(https://www.khanacademy.org/math/probability/statistics-inferential/confidence-intervals/v/confidence-interval-1).

This is the first exercise I've written, so please let me know if it meets your standards, and what I can do to improve it.

Thanks!