In this case, we'll have to carry out several steps to find the solution.
Step 01:
Data:
Bus Route Table
Route average ≅ 30min
Goal:
mean absolute deviation = 0.5 minute
Step 02:
Average:
average = (29.7 + 30.1 + 29.5 + 29.6 + 30.2 + 29 + 31 + 29.8 + 30.2) / 9
average = 29.9
Deviations:
29.7 - 29.9 = -0.2
30.1 - 29.9 = 0.2
29.5 - 29.9 = -0.4
29.6 - 29.9 = -0.3
30.2 - 29.9 = 0.3
29 -29.9 = -0.9
31 - 29.9 = 1.1
29.8 - 29.9 = -0.1
30.2 - 29.9 = 0.3
Mean absolute deviation:
Mean absolute deviation = (0.2 + 0.2 + 0.4 + 0.3 + 0.3 + 0.9 + 1.1 + 0.1 + 0.3 ) / 9 = 3.8 / 9 = 0.422...
The answer is:
Mean absolute deviation = 0.422...
Yes, because the mean absolute deviation is 0.42