Comparing the performance of Airlines based on Z-scores.
The average lateness for Airline A is 10 minutes. The variance of lateness measure is calculated as 9. One of its airplanes arrived 8.5 minutes after the stated arrival time. The average lateness for Airline B is 13 minutes with the standard deviation of 4 minutes. One of its airplanes arrived 7 minutes late. Which airplane performed better regarding lateness?