Question

At a local restaurant, the amount of time that customers have to wait for their food is normally distributed with a mean of 20 minutes and a standard deviation of 5 minutes. Using the empirical rule, what percentage of customers have to wait between 5 minutes and 35 minutes?

Answer 1

Answer: About 99.7% of the population wait between 5 minutes and 35 minutes.

Explanation:

According to the Empirical rule,

If a population is normally distributed, then

About 99.7% of the population lies within 3 standard deviations from the mean.

Here, Population is normally distributed with Mean = 20 minutes , standard deviation = 5 minutes

By empirical rule,

About 99.7% of the population wait between (20-3(5)) minutes and (20+3(5)) minutes.

About 99.7% of the population wait between 5 minutes and 35 minutes.