At a local restaurant, the amount of time that customers have to wait for their food is normally distributed with a mean of 18 minutes and a standard deviation of 2 minutes. What is the probability that a randomly selected customer will have to wait less than 15 minutes, to the nearest thousandth?
Q. At a local restaurant, the amount of time that customers have to wait for their food is normally distributed with a mean of 18 minutes and a standard deviation of 2 minutes. What is the probability that a randomly selected customer will have to wait less than 15 minutes, to the nearest thousandth?
Calculate z-score: To find the probability, we need to calculate the z-score for 15 minutes.Z=σX−μWhere X is 15 minutes, μ is the mean (18 minutes), and σ is the standard deviation (2 minutes).Z=215−18
Calculate z-score: Calculate the z-score.Z=2−3Z=−1.5
Look up in table: Now we look up the z-score in the standard normal distribution table to find the probability. The table gives the probability that a value is less than a given z-score.
Find probability: The probability for Z=−1.5 is approximately 0.0668.
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