Lovell Levelers, Inc. is a major provider of specialized parts for the automotive industry. LLI's biggest customer, Specific Motors was not a delighted customer this month. In fact, last Monday, the executive vice president of Specific Motors headquarters, Phyllis Kendall was diverted from a return trip from Singapore to drop in unexpectedly at the LLI plant. There was nothing routine about this visit. She made it explicitly clear that Specific Motors was disappointed with the level of quality relative to the leveler plates. In particular, she was disappointed with the current average of rejects at the rate of 1,350 defects per million opportunities (DPMO) at a cost of poor quality of just over $256,000 per quarter. She said the industry standard is less than 50 DPMO and if we do not get the level of quality to the industry standard (as a minimum) within the next six months, LLI should not expect
to keep the business next year.
The student will be a Black Belt working for LLI. The specifics about their company:
CEO Bill Lovell
GM Mary Nichols
Sponsor John Hopps
Finance Cindy Jenkins
Process owner Leroy Miller
Master BB Dennis Kens
Manufacturing Mitch Freese
Design Engineer Al Nelson
Quality Debbie Judson
See the attached file. Thanks.
There is thought among some people at your facility that the old method and the new method are producing product at different thicknesses.
You DO NOT WANT the methods to be different. In fact, you want the methods to be producing products that are the same. To address this, you suggest using a T test. If the methods are significantly different, you have a problem.
If the null is NOT rejected--that is good news! The team agrees that a sample size of 25 is adequate for the test. Remember, you are hoping the null does not get rejected. The team decides a significance level at 0.05 for the test.
Instructions for you:
Step 1. You need 4 numbers:
Old method's average: m = ...
This posting covers a Black Belt project, Analyze Phase of DMAIC. Expected variation and T test are reviewed.