Estimate the percentage of one-year-old girls in the US that meet the following conditions. So when they say that without a calculator estimate, that's a big clue or a big giveaway that we're supposed to use the empirical rule. The empirical rule. Sometimes called the 68-95-99.7 rule. And this is actually, if you remember, this is the name of the rule. You've essentially remembered the rule. What that tells us is if we have a normal distribution, I'll do a bit of a review here before we jump into this problem.