8/18/2019 PracticeProblems_QualityManagement.pdf

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8/18/2019 PracticeProblems_QualityManagement.pdf

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15. Design specifications require that a key dimension on a product measures100 ± 10 units. A process being considered for producing this product has astandard deviation of four units and an average of 92 units.

a) 

What can you say (quantitatively) regarding the process capability?

b) 

Suppose the process average shifts to 100 and the standard deviation isreduced to 10/3 (= 3.3333) units. Calculate the new process capability.

c) 

What can you say about the process after the shift? Approximately whatpercentage of the items produced will be defective?

d) 

With the process after the shift, if the producer wants to achieve a six-sigma process, by at least how much does he have to reduce thestandard deviation?

Note: question 15 is slightly modified from the question in the book.