1. Specifications for a part for a DVD player state that the part should weigh between 24.6 and 25.6 ounces. The process that produces the parts has a mean of 25.1 ounces and a standard deviation of .26 ounce. The distribution of output is normal. Use Table-A.
a. What percentage of parts will not meet the weight specs?
b. Within what values will 95.44 percent of sample means of this process fall, if samples of n = 9 are taken and the process is in control (random)?
2. Specifications for the computer upgrades are 77 minutes and 81 minutes. Estimate the percentage of process output that can be expected to fall within the specifications.
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SAMPLE
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1
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2
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3
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4
|
5
|
6
|
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79.2
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81.9
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79.6
|
78.9
|
82.1
|
79.7
|
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82.6
|
78.7
|
79.6
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80.2
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79.6
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80.6
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80.0
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81.0
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79.8
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79.7
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80.4
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78.5
|
|
78.4
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80.4
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80.3
|
79.4
|
79.7
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80.0
|
|
81.0
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80.1
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80.8
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80.6
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78.8
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81.1
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3. A production process consists of a three-step operation. The scrap rate is 20 percent for the first step and 11 percent for the other two steps.
a. If the desired daily output is 500 units, how many units must be started to allow for loss due to scrap?
b. If the scrap rate for each step could be cut in half at every operation, how many units would this save in terms of the scrap allowance?
c. If the scrap represents a cost of $10 per unit, how much is it costing the company per day for the original scrap rate (i.e. the Part a scrap rate)?