Answer:
(14, 22)
Explanation:
The amount of time that customers have to wait for their food is normally distributed with:
[tex]undefined[/tex]• Mean = 18 minutes
,• Standard deviation = 4 minutes.
The Empirical Rule
For normal distributions, the empirical rule states that:
• 68% of observed data points will lie inside one standard deviation of the mean.
,• 95% will fall within two standard deviations
,• 99.7% will occur within three standard deviations.
By the empirical rule, 68% of observed data points will lie inside one standard deviation of the mean.
Therefore, the interval of minutes that the middle 68% of customers have to wait is:
[tex](\mu-\sigma,\mu+\sigma)=(18-4,18+4)=(14,22)[/tex]The interval is (14, 22).
