ABC Company is currently considering using one of several suppliers for a new part. For the part, ABC Company's upper specification limit (USL) is 12.6 centimeters (cm) and its lower specification limit (LSL) is 9.9 centimeters (cm). ABC Company wants both the process capability ratio and process capability index to be at least 1.20 at the minimum.
Three Company has a process whose standard deviation is 0.36 cm but the mean of its process is not known. Three Company says it cannot or will not be able to change the standard deviation of its process.
What is the range (the upper and lower limits) on the mean of the process to maintain a Cpkof 1.2 or greater?