The machine shop in a manufacturing plant makes three gears that fit together to become part of the gear shift mechanism for a forklift.Each part must be a specific diameter within specific tolerances.The three parts,when put together to slip into the gearbox,must also meet an overall diameter within a specific tolerance. "Nominal" is the intended or target diameter of the part. "Tolerance" is the amount of variation that is considered acceptable. For example, Part 1 should have a diameter of 1.750 inches, but the part will be considered acceptable if its diameter is as small as 1.708 inches or as large as 1.792 inches. See Figure 1 and Table 1 below.

Part Nominal (inches) Tolerances (inches) 1 1.750 + 0.042 2 2.000 + 0.060 3 1.250 + 0.030 Table 1 - Specifications Figure 1 - Three GearsSample # Part 1 Part 2 Part 3 1 1.74831 2.01144 1.25426 2 1.75740 2.00448 1.24775 3 1.75134 2.01492 1.24558 4 1.73316 2.00448 1.24992 5 1.75134 2.00448 1.23907 6 1.71498 2.00100 1.25860 1.75437 2.00796 1.25643 8 1.73619 2.00100 1.25209 9 1.73922 1.98708 1.25426 10 1.73619 1.99752 1.24341 11 1.74528 1.99752 1.25643 12 1.74831 2.00100 1.24775 13 1.76346 1.99404 1.24341 14 1.74528 2.00796 1.24558 15 1.76952 2.00448 1.23907 16 1.70892 2.00448 1.24124 17 1.75134 2.00100 1.24558 18 1.71195 1.99752 1.24992 19 1.74831 2.00100 1.25209 20 1.77861 2.00100 1.24992 21 1.75740 1.98708 1.24992 22 1.73619 1.99404 1.24558 23 1.74225 1.98708 1.24992 24 1.74528 1.98360 1.24775 25 1.73922 2.00100 1.24775 Mean Std.Dev. UCL LCL Table 2 - Sample Diameters