| 5-50 A normally distributed quality characteristic is monitored through use of an x and an R chart. |
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| There charts have the following parameters(n=4) |
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x Chart |
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R Chart |
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UCL=626.0 |
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UCL=18.795 |
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CL=620.0 |
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CL=8.236 |
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LCL=614.0 |
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LCL=0 |
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| Both charts exhibit control. |
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| (a)What is the estimated standard deviation of the process? |
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| (b)Suppose an s chart were to be substituted for the R chart. |
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| What would be the appropriate parameters of the s chart? |
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| (c)If specifications on the product were 610+-15,what would be |
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| your estimate of the process fraction nonconforming? |
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| (d)What could be done to reduce this fraction nonconforming? |
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| (e)What is the probability of detecting a shift in the process |
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| mean to 610 on the first sample following the shift (s remains constant)? |
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| (f)What is the probability of detecting the shift in part e by at least the thind sample after the shift occurs? |
