The deviation, means from the shortest height to the tallest height can have a difference of 3 inches.
Using 42 as a midpoint, you would subtract half the deviation to find the shortest value and add half the deviation to find the tallest value:
3/2 = 1.5
42 - 1.5 = 40.5
42 + 1.5 = 43.5
Minimum = 40.5 inches.
Maximum = 43.5 inches.
