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# The resting heart rates for a sample of individuals are normally distributed with a mean of 70 and a standard deviation of 15. How do you find the percentage of heart rates less than 85?

## Use the 68-95-99.7 rule.

The empirical rule states that 68% values are within 1 standard deviation of mean, i.e, $70 \setminus \pm 15$ or from 55 to 85. Since normal distribution is symmetric, we must have (32%) outside this range, and 32/2=16% on the right if this range. Hence below 85 we have (100-16) % = 84%