Concept explainers
a)
To establish: The
Introduction: Control charts used to determine whether the process is under control or not. Attributes and variables are the factors under the control charts.
b)
To determine: Why the lower control limit cannot be a negative number.
Introduction: Control charts used to determine whether the process is under control or not. Attributes and variables are the factors under the control charts.
c)
To determine: The implication of having 0.10 and 0.01 as upper and lower control limit on Bank B.
Introduction: Control charts used to determine whether the process is under control or not. Attributes and variables are the factors under the control charts.
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Principles of Operations Management: Sustainability and Supply Chain Management (10th Edition)
- Management at Webster Chemical Company is concerned as to whether caulking tubes are being properly capped. If a significant proportion of the tubes are not being sealed, Webster is placing its customers in a messy situation. Tubes are packaged in large boxes of 135. Several boxes are inspected, and the following numbers of leaking tubes are found: View an example Sample 1 2 3 Get more help. 4 Tubes 7 7 8 5 1 5 6 7 Calculate p-chart three-sigma control limits to assess whether the capping process is in statistical control. The UCL, equals 1 Sample 8 8 9 10 11 12 13 14 Tubes 7 2 4 8 6 9 MacBook Pro 3 Sample 15 16 17 18 19 20 Total Tubes 8 3 3 5 and the LCL equals (Enter your responses rounded to three decimal places. If your answer for LCL, is negative, enter this value as 0.) 3 6 104 Clear all Check answer Oarrow_forwardThe overall average on a process you are attempting to monitor is 60.0 units. The process population standard deviation is 1.72. Sample size is given to be 4. Part 2 a) Determine the 3-sigma x-chart control limits. Upper Control Limit (UCLx)=enter your response here units (round your response to two decimal places). Part 3 Lower Control Limit (LCLx)=enter your response here units (round your response to two decimal places). Part 4 b) Now determine the 2-sigma x-chart control limits. Upper Control Limit (UCLx)=enter your response here units (round your response to two decimal places). Part 5 Lower Control Limit (LCLx)=enter your response here units (round your response to two decimal places). Part 6 How do the control limits change? A. The control limits are tighter for the 3-sigma x-chart than for the 2-sigma x-chart. B. The control limits for the 2-sigma x-chart and for the 3-sigma x-chart are the same. C. The control limits…arrow_forwardAt Gleditsia Triacanthos Company, a certain manufactured part is deemed acceptable if its lengthis between 12.45 to 12.55 inches. The process is normally distributed with an average of 12.49inches and a standard deviation of 0.014 inches. A) Is the process capable of meeting specifications? B) Does the process meet specifications?arrow_forward
- Quality control in a factory pulls 40 parts with paint, packaging, or electronic defects from anassembly line. Of these, 28 had a paint defect, 17 had a packaging defect, 13 had an electronicdefect, 6 had both paint and packaging defects, 7 had both packaging and electronics defects, and 10had both paint and electronic defects. Did any part have all three types of defect? If so, how many?arrow_forwardWest Battery Corp. has recently been receiving complaints from retailers that its 9-volt batteries are not lasting as long as other name brands. James West, head of the TQM program at West's Austin plant, believes there is no problem because his batteries have had an average life of 60hours, about 10% longer than competitors' models. To raise the lifetime above this level would require a new level of technology not available to West. Nevertheless, he is concerned enough to set up hourly assembly line checks. Previously, after ensuring that the process was running properly, West took samples of 5 9-volt batteries for 25 test to establish the standards for control chart limits. Those 25 tests are shown in the following table: Sample Data Sample Data Hour Sample Taken 1 2 3 4…arrow_forwardAn e-commerce website has received some complaints on Billing errors. Managers ask the accounting department to monitor the shipping process and make sure of the quality in their process. To monitor the process, for 10 consecutive weeks, they look into the first 100 shipments and count the number of Billing errors as shown in table below: 45 52 6 3 63 7 8 9 10 1 6 1 2 Construct a two-sigma limit control chart to show whether the shipping process in this e-commerce firm needs any improvement or performs at an acceptable level. (Round your answer to three decimal places.) Week 1 2 3 Number of Billing errors. 5 1 3 Upper Control Limit Lower Control Limitarrow_forward
- An automatic filling machine is used to fill 1-liter bottles of cola. The machine’s output is approximately normal with a mean of 1.0 liter and standard deviation of .01 liter. Output is monitored using means of samples of 25 observations. Determine upper and lower control limits that will include roughly 97% of the sample means when the process is in control. Using Appendix B, Table A to find the value of Z corresponding to the mean control limits.arrow_forwardOrganic Grains LLC uses statistical process control to ensure that its health-conscious, low-fat, multigrain sandwich loaves have the proper weight. Based on a previously stable and in-control process, the control limits of the x- and R-charts are: UCL-4.86, LCL- = 4.52, UCLR=1.344, LCLR = 0. Over the past few days, they have taken five random samples of four loaves each and have found the following: Based on the x-chart, is one or more samples beyond the control limits? Sample 1 2 3 4 5 Yes No Loaf # 1 4.8 4.4 4.5 4.6 5.0 Net Weight Loaf # 2 4.7 4.8 4.5 4.9 4.8 Loaf # 3 5.0 4.7 4.9 4.7 4.7 Loaf # 4 4.7 4.8 4.6 4.5 4.6arrow_forwardInter-State Moving and Storage Company wishes to establish a control chart to monitor the proportion of residential moves that result in written complaints due to late delivery, lost items, or damaged items. A sample of 40 moves is selected for each of the last 12 months. The number of written complaints in each sample is 9, 7, 4, 9, 1, 9, 11, 5, 5, 8, 7, and 15. Number Defective Percent defective 9 18 7 14 4 8 9 18 1 2 9 18 11 22 5 10 5 10 8 16 7 14 15 30 a. Insert the mean proportion defective, UCL, and LCL. (Leave no cells blank - be certain to enter "0" wherever required. Round your intermediate calculations and final answers to 2 decimal places.) Mean proportion defective UCL LCL c. Does it appear that the number of complaints is out of control for any of the months?multiple choice Yes Noarrow_forward
- Using samples of 200 credit card statements, an auditor found the following: Sample 1 2 3 4 Number with errors 4 2 5 9 a. Determine the fraction defective in each sample. b. If the true fraction defective for this process is unknown, what is your estimate of it? c. What is your estimate of the mean and standard deviation of the sampling distribution of fractions defective for samples of this size? d. What control limits would give an alpha risk of .03 for this process? Page 457 e. What alpha risk would control limits of .047 and .003 provide? f. Using control limits of .047 and .003, is the process in control? g. Suppose that the long-term fraction defective of the process is known to be 2 percent. What are the values of the mean and standard deviation of the sampling distribution? h. Construct a control chart for the process, assuming a fraction defective of 2 percent, using two-sigma control limits. Is the process in control? Can you show me the steps and formulas using excelarrow_forwardAuto pistons at Wemming Chung's plant in Shanghai are produced in a forging process, and the diameter is a critical factor that must be controlled. From sample sizes of 10 pistons produced each day, the mean and the range of this diameter have been as follows: a) What is the value of x? x= 156.76 mm (round your response to two decimal places). b) What is the value of R? Day 1 2 3 4 5 Mean x (mm) 158.9 155.2 155.6 157.5 156.6 R = 4.40 mm (round your response to two decimal places). c) What are the UCL and LCL using 3-sigma? Upper Control Limit (UCL) = mm (round your response to two decimal places). Range R (mm) 4.2 4.4 4.3 4.8 4.3 Çarrow_forwardFactors for Computing Control Chart Limits (3 sigma) Auto pistons at Wemming Chung's plant in Shanghai are produced in a forging process, and the diameter is a critical factor that must be controlled. From sample sizes of 10 pistons produced each day, the mean and the range of this diameter have been as follows: Day Mean x (mm) Range R (mm) 1 156.9 4.2 2 153.2 4.6 3 153.6 4.1 4 155.5 5.0 5 156.6 4.5 Part 4 c) What are the (UCLx) and (LCLx) using 3-sigma? (UCLx) = mm (round your response to two decimal places). (LCLx) = mmarrow_forward
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