Question

The average lateness for one of the top airline companies is 10 minutes. The variance of the lateness measure is calculated as 9. An airplane arrived 13 minutes after the stated arrival time. Calculate the z-score for the lateness of this particular airplane.

Answer 1

The z score for the airplane arriving 13 minutes after arrival time is 0.33

Explanation:

Using normal distribution,

The average lateness for one of the top airline companies is 10 minutes. So our mean, u = 10

The variance, s of the lateness measure is calculated as 9.

x =13 which stands for arrival time.

Using normal distribution,

z = (x - u)/s

z = (13 - 10)/9 = 3/9 = 0.33

The z score for the airplane arriving 13 minutes after arrival time is 0.33. The probability value of the z score can be found by looking at the Normal distribution table