The MPG (miles per gallon) for a certain compact car is normally distributed with a mean of 31 and a standard deviation of 0.8. What is the probability that the MPG for a randomly selected compact car would be less than 32?
A)0.3944
B)0.8944
C)0.1056
D)0.5596

Question

Quizplus · Accepted Answer

We need to find the z-score for a MPG of 32:
z = (x - μ) / σ = (32 - 31) / 0.8 = 1.25
Then, we look up the area to the left of this z-score in the standard normal distribution table (or use a calculator):
P(z < 1.25) = 0.8944
Therefore, the probability that the MPG for a randomly selected compact car would be less than 32 is 0.8944, or 89.44%.

The MPG (Miles Per Gallon) for a Certain Compact Car