Introduction to Operations Management (IDS 532)
Assignment 3: Queuing and Quality
Possible points: 20
Note: The data for Q1 and Q2 can be found in the Excel file titled “A3Data.xlsx”.
1. Electronic Circuit Manufacturing (10 points)
Resistors for electronic circuits are manufactured on a high-speed automated machine. The machine is setup to produce a large run of resistors of 1,000 ohms each. To setup the machine and create a control chart to be used throughout the run, 15 samples were taken with four resistors in each sample. The complete list of samples and their measured values are given in the "resistor" sheet in the Assignment 3 Excel file.
Develop an x-chart and plot the values. From the chart, what comments can you make about the process? (Use three-sigma control limits)
2. State and Local Police (10 points)
The state and local police departments are trying to analyze crime rates so they can shift their patrols from decreasing-rate areas to areas where rates are increasing. The city and county have been geographically segmented into areas containing 5,000 residences. The police recognize that not all crimes and offenses are reported: People do not want to become involved, consider the offenses too minor to report, are too embarrassed to make a police report, or do not take the time, among other reasons. Every month, because of this, the police contact a random sample of 1,000 of the 5,000 residences by phone for data on crimes.
(Respondents are guaranteed anonymity.) The sheet named “police” in the Assignment 3 Excel file contains crime data collected for one area over the past 15 months.
Construct a p-chart for 95% confidence (1.96 sigma or approx. 2 sigma) and plot each of the months.
What comments can you make regarding the crime rate in the last three months?