Question

In: Statistics and Probability

The following represents the number of solder defects on 24 samples on ve printed circuit boards;...

The following represents the number of solder defects on 24 samples on ve printed circuit boards; 7,6,8,10,24,6,5,4,8,11,15,8,4,15,11,12,8,6,5,9,7,14,8,21.

(a) Using all the data, compute trial control limits for a U control chart, construct the chart and plot the data.

(b) Can we conclude that the process is in control using a U chart? If not, assume assignable causes can be found, list points and revise the control limits.

Solutions

Expert Solution

ANSWERS:

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Ans a)

Control limits for U chart is,

Upper control limits are = 0.729

Lower control limits are = 0.014

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Graph:

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Ans b)

The process is not in control.

One point more than 3.00 standard deviations from the centerline.
Test Failed at points: 5, 24

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If you want upper and lower control limits manually calculation then comment please below I will provide an answer definitely, thank you.


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