# Empirical rule

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### Problem

The lifespans of zebras in a particular zoo are normally distributed. The average zebra lives 20, point, 5 years; the standard deviation is 3, point, 9 years.
Use the empirical rule left parenthesis, 68, minus, 95, minus, 99, point, 7, percent, right parenthesis to estimate the probability of a zebra living between 16, point, 6 and 24, point, 4 years.
percent
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