# MKS Inc., produces meter sticks that have a target length of 100 centimeters with upper and lower...

## Question:

MKS Inc., produces meter sticks that have a target length of 100 centimeters with upper and lower specification limits of 100.05 and 99.95 centimeters respectively. Their existing process produces meter sticks with an average length of 99.97 centimeters and a standard deviation of 0.015 centimeters.

What is their process capability index?

## Process Capability Index:

Process capability index refers to a tool in statistics, which helps in measuring the ability of a particular process in order to produce the output on the basis of specification limits of the customers.

Given that:

• Lower specification Limit (LSL) = 99.95
• Upper specification Limit (USL) = 100.05
• Mean = 99.97
• Standard Deviation (Sd) = 0.015

Cpu = (USL - Mean) / (3 * Sd)

=> (100.05 - 99.97) / (3 * 0.015)

=> 0.08 / 0.045

=> 1.78

Cpl = (Mean - LSL) / (3 * Sd)

=> (99.97 - 99.95) / (3 * 0.015)

=> 0.02 / 0.045

=> 0.44

Process capability index = minimum of (cpu, cpl)

=> minimum (1.78, 0.44)

=> 0.44

Process Capability: Definition & Elements

Chapter 4 / Lesson 5
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