Question

The average gas mileage of a certain model car is 29.0 miles per gallon. If the gas mileages are normally distributed with a standard deviation of 0.6 miles per gallon, find the probability that a car has a gas mileage of between 28.8 and 29.2 miles per gallon.

Answer 1

first calculate the z score with the two values given, 28.8 and 29.2
then look up on the z score table what the confidence interval would be for each, then subtract the larger confidence inteval from the smaller confidence interval obtained, and you will have the probability of finding a car that has a gas mileage between 28.8 and 29.2

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