Khan Academy on a Stick
ck12.org normal distribution problems: Empirical rule
Using the empirical rule (or 68-95-99.7 rule) to estimate probabilities for normal distributions
If the above player doesn't work, try this direct link.
Using the empirical rule (or 68-95-99.7 rule) to estimate probabilities for normal distributions
If the above player doesn't work, try this direct link.