A company making tires for bikes is concerned about the exact width of their cyclocross tires. The company has a lower specification limit of 19.840 mm and an upper specification limit of 19.99 mm. The standard deviation is 0.28 mm and the mean is 19.915 mm.

(a) What is the process capability index for the process? (Round the answer to 5 decimal places.)

(b) The company now wants to reduce its defect probability and run a "six-sigma process." To what level would they have to reduce the standard deviation in the process to meet this target? (Round the answer to 5 decimal places.)