A study found that the mean amount of time cars spent in? drive-throughs of a certain? fast-food restaurant was 156.3 seconds. Assuming? drive-through times are normally distributed with a standard deviation of 28 ?seconds, complete parts? (a) through? (d) below.
?(a) What is the probability that a randomly selected car will get through the? restaurant's drive-through in less than 112 ?seconds?
The probability that a randomly selected car will get through the? restaurant's drive-through in less than 112 seconds is _______.
?(Round to four decimal places as? needed.)
?(b) What is the probability that a randomly selected car will spend more than 201 seconds in the? restaurant's drive-through? The probability that a randomly selected car will spend more than 201 seconds in the? restaurant's drive-through is_______.
?(Round to four decimal places as? needed.)
?(c) What proportion of cars spend between 2 and 3minutes in the? restaurant's drive-through? The proportion of cars that spend between 2 and 3 minutes in the? restaurant's drive-through is______. ?(Round to four decimal places as? needed.)
?(d) Would it be unusual for a car to spend more than 3 minutes in the? restaurant's drive-through?? Why? The probability that a car spends more than 3 minutes in the? restaurant's drive-through is _______ than 0.05. (Round to four decimal places as? needed.)