Question

At a local restaurant, the amount of time that customers have to wait for their food is normally distributed with a mean of 32 minutes and a standard deviation of 2 minutes. Using the empirical rule, what percentage of customers have to wait between 26 minutes and 38 minutes?

Answer 1

26 minutes is 32 − 6 = 32 − 3(2) and 38 minutes is 32 + 6 = 32 + 3(2), i.e. ±3σ. By the empirical rule about 99.7% of customers wait between 26 and 38 minutes.