Operations Management 200.Doc

MGT2320 Online – Assignment 3

There are 5 questions.

You must show all calculations.

1. A list of 7 defects that lead to defects and the number of occurrences in a printed-circuit-board assembly line appear below:

|Defect |Number of Defect Occurrences |

|Components not adhering |143 |

|Excess adhesive |71 |

|Misplaced transistors |601 |

|Defective board dimension |146 |

|Mounting holes improperly positioned |12 |

|Circuitry problems on final test |90 |

|Wrong components |212 |

A) Prepare a Pareto analysis the data. (2 marks)

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B) What conclusions can you draw from the analysis? (2 marks)

From the above pareto chart we find that nearly 75% of the problems are caused by "defective board dimension" or "Wrong components" or "Misplaced transistors". This is close to the 80-20 law that suggests 80% of the problem can be traced to 20% of the sources.

2. Thirty-five samples of size 7 each were taken from a fertilizer bag filling machine. The results were: overall mean = 57.75 kg, average range = 1.78 kg.

A) Determine the upper and lower control limits of the X bar chart where...