Final answer:
To find the z-score of Carmen's commute distance, subtract the mean from her commute distance and divide by the standard deviation. Her z-score is approximately 0.78, meaning her commute is 0.78 standard deviations longer than the average.
Step-by-step explanation:
The z-score is a statistical measure that tells us how many standard deviations an element is from the mean of the distribution. To calculate the z-score for Carmen's commute distance, we use the formula:
Z = (X - μ) / σ
Where X is Carmen's commute distance, μ (mu) is the mean of the commute distances, and σ (sigma) is the standard deviation. Given that the mean commute distance is 15 kilometers and the standard deviation is 9 kilometers, and Carmen's commute distance is 22 kilometers:
Z = (22 - 15) / 9
Z = 7 / 9
Z = 0.78
So the z-score of Carmen's commute distance is approximately 0.78. This means Carmen's commute is 0.78 standard deviations longer than the average commute.