Answer: 26.3 mm Step-by-step explanation: According to the two-standard deviations rule for outliers, the values that does not lie within 2 standard deviations from mean are outliers. If Mean = 23.5 millimeters (mm) and standard deviation = 1.4 mm Then, greatest thickness need to check = mean + 2 (standard deviation) = 23.5 + 2(1.4) = 23.5 + 2.8 = 26.3 mm hence, the greatest thickness that would require the statistician to check the configuration of the machine = 26.3 mm.