Suppose the number of gallons of gasoline per day used by a car is normally distributed with a mean of 2.2 gallons and a standard deviation of 1.2 gallons.
What is the difference in gallons per day used by a car with a z-score of 3 and another car that has a z-score of 0?
The z-score counts the number of standard deviations from the mean. Then the meaning in gallons of a difference in z-score is found by multiplying the z-score difference by the value of a standard deviation.
