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Module 4 — Statistical Quality
Covers statistical quality tools applied to apparel manufacturing.
What you will be able to do
Use measurement-system analysis, control charts and capability indices to say whether a process is stable and able to hold the specification.
The practical work
Collect twenty subgroups of measurements from one operation, chart them, and separate common-cause variation from special causes before touching the process. Run a short measurement-system study on the same operation to see how much of the variation is the gauge and the operator. Then calculate capability against the tolerance and state honestly whether the tolerance is achievable.
Prerequisite: Read module 3 and pass its quiz first.
Reading for this module
Read these 3 Garment Ed subjects in order, then take the quiz below.
Practical worksheet
Collect twenty subgroups of measurements from one operation, chart them, and separate common-cause variation from special causes before touching the process. Run a short measurement-system study on the same operation to see how much of the variation is the gauge and the operator. Then calculate capability against the tolerance and state honestly whether the tolerance is achievable.
- Identify requirements and assumptions.
- Record evidence and calculations.
- Choose a decision and containment action.
- Assign an owner and verification check.
Module quiz
5 questions on Module 4 — Statistical Quality. Answer them all, then check your score before moving on. 4 correct or more is a pass. Your best score is saved on this device, and to your account when you are signed in. This is a self-check, not an accredited assessment.
1. What does a point beyond the upper control limit on an X-bar chart indicate?
2. Control limits and specification limits are:
3. A process has Cp 1.6 but Cpk 0.7. What does that mean?
4. Measurement-system analysis shows the gauge and operator account for 40% of total variation. What follows?
5. Twenty subgroups show no special causes but 6% of pieces fall outside tolerance. What is the honest conclusion?
Applied assessment
Tell special-cause from common-cause variation and judge whether a process can hold a specification. 8 questions that ask you to decide or calculate from a real situation, 75 per cent to pass, unlimited attempts.
Take the applied assessmentStructured certification
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