A laser eye surgery process has tolerances of plus or minus .001 inches. What does the process standard deviation need to be in order for this process to have a capability ratio of 1.33?
A) 0.025 inches
B) 0.0015 inches
C) 0.015 inches
D) 0.00025 inches

Question

Quizplus · Accepted Answer

The capability ratio (Cp) is calculated as (USL - LSL) / (6 * standard deviation). Given the tolerances are ±0.001 inches, the total tolerance range is 0.002 inches. For a Cp of 1.33, the equation is 0.002 / (6 * standard deviation) = 1.33. Solving for the standard deviation gives approximately 0.00025 inches.

A Laser Eye Surgery Process Has Tolerances of Plus or Minus