The average gas mileage of a certain model car is 28 miles per gallon. If the gas

mileages are normally distributed with a standard deviation of 1.7, find the probability

that a car has a gas mileage of between 27.8 and 28.3 miles per gallon.

Answer: The probability is 0.3432.

Step-by-step explanation:

mu = 28, sigma = 0.45, x1 = 27.8, x2 = 28.

z1 = (x1 - mu) / sigma

z1 = (27.8 - 28) / 0.45 = - 0.4444

z2 = (x2 - mu) / sigma = (28.2 - 28) / 0.45 = 0.4444

P (27.8 < x < 28.2) = P (-0.4444 < z < 0.4444) = 0.3432