Concept explainers
a
Interpretation:
The control limits for
Concept Introduction:Control charts are used to measure the effectiveness of the process determining the average value and control limits of the process. The Upper Control Limit (UCL) is the larger value and the Lower Control limit (LCL) is the smaller value of the sample
b
Interpretation:
Probability that the shift is detected in the first subgroup after the shift occurs.
IConcept Introduction:Control charts are used to measure the effectiveness of the process determining the average value and control limits of the process. The Upper Control Limit (UCL) is the larger value and the Lower Control limit (LCL) is the smaller value of the sample
c
Interpretation:
The number of subgroups that would be required to sample before it was detected and after the shift has occurred
IConcept Introduction:Control charts are used to measure the effectiveness of the process determining the average value and control limits of the process. The Upper Control Limit (UCL) is the larger value and the Lower Control limit (LCL) is the smaller value of the sample
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Production and Operations Analysis, Seventh Edition
- What is the meaning of x ~ N (50, 20)? 1. Sampling distribution of x is distributed with a mean of 20 and a standard deviation of 50 2. x-bar is normally distributed with a mean of 20 and a standard deviation of 50 3. x is normally distributed with a mean of 50 and a standard deviation of 20 4. Sampling distribution of x is distributed with a mean of 50 and a standard deviation of 20arrow_forwardRefer to Table S6.1 - Factors for Computing Control Chart Limits (3 sigma) for this problem. Twelve samples, each containing five parts, were taken from a process that produces steel rods at Emmanual Kodzi's factory. The length of each rod in the samples was determined. The results were tabulated and sample means and ranges were computed. The results were: Sample Mean (in.) Range (in.) Sample Sample Sample Mean (in.) Range (in.) 1 9.404 0.044 7 9.403 0.021 2 9.402 0.051 8 9.405 0.058 3 9.393 0.042 9.395 0.039 4 9.404 0.037 10 9.401 0.038 9.399 0.048 11 9.401 0.054 9.397 0.053 12 9.404 0.061 For the given data, the x = inches (round your response to four decimal places). Based on the sampling done, the control limits for 3-sigma x chart are: Upper Control Limit (UCL;) = inches (round your response to four decimal places). Lower Control Limit (LCL;) = inches (round your response to four decimal places).arrow_forwardBill Kime's bowling ball factory makes bowling balls of adult size and weight only. The standard deviation in the weight of a bowling ball produced at the factory is known to be 0.39 pounds. Each day for 24 days, the average weight, in pounds, of 9 of the bowling balls produced that day has been assessed as follows Day 1 2 3 4 5 6 Average (lb) 9.9 9.9 10.1 10.1 99 99 Day 7 8 9 10 11 12 Average (lb) Day Average (b) 13 14 15 16 17 18 10.1 10.0 10.0 10.1 10.1 10.0 9.9 10.1 10.1 10.0 10.1 10.1 Day 19 20 21 22 23 24 Average (lb) 99 10.0 10.1 9.9 10.0 10.0 a) Establish a control chart for monitoring the average weights of the bowling balls in which the upper and lower control limits are each two standard deviations from the mean What are the values of the control limits? Upper Control Limit (UCL)=b (Round your response to two decimal places)arrow_forward
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- A manufacturer is selling pharmaceuticals that have a weight specification 199.8 to 200.2 mg, with a target value of 200 mg. Before sending its next shipment, the company collects a large sample of product and determines the mean weight of the sample is 199.89 mg, with a standard deviation of 0.035 mg. The process capability index for the current process is ____. Round to three decimal places.arrow_forwardResistors for electronic circuits are manufactured on a high-speed automated machine. The machine is set up to produce a large run of resistors of 1,000 Ohms each. To set up the machine and to create a control chart to be used throughout the run, 15 samples and their measured values are as follows: Sample Number Readings (in Ohms) 1 1010 991 985 986 2 995 996 1009 994 3 990 1003 1015 1008 4 1015 1020 1009 998 5 1013 1019 1005 993 6 994 1001 994 1005 7 989 992 982 1020 8 1001 986 996 996 9 1006 989 1005 1007 10 992 1007 1006 979 11 996 1006 997 989 12 1019 996 991 1011 13 981 991 989 1003 14 999 993 988 984 15 1013 1002 1005 992 Develop three-sigma appropriate control chart(s) from the chart(s) what comments can you make about the process? Explain and show workarrow_forwardA pharmaceutical company producing vitamin capsules desires a proportion of calcium content between 40 and 55 ppm. A random sample of 20 capsules chosen from the output yields a sample mean calcium content of 44 ppm with a standard deviation of 3 ppm. Find the natural tolerance limits of the process. If the process is in control at the present values of its parameters, what proportion of the output will be nonconforming, assuming a normal distribution of the characteristic? Answer letters a, b, and c. a. Find the Cp index. Comment on the ability of the process to meet specifications. b. What proportion of the specification range is used up by the process? c. If it is easier to change the process mean than to change its variability, to what value should the process mean be set to minimize the proportion of nonconforming product?arrow_forward
- A machine is used to fill cans of motor oil additive. A single sample can is selected every hour and the net weight of the can is obtained. Since the filling process is automated, it has very stable variability, and long experience indicates that s = 0.02 oz. The process target (process mean when in control) is 8.02 oz. A tabular cusum is being used for this process with standardized values h=4.5 and k=0.5. If the values of Cumulative sums at the end of measurement 7 were C," + = 0.030 and C,¯ = 0.0 , and measurement 8 is equal to Xg = 8.071, what will be the Cumulative sum at the end of measurement 8, that is C3 + = ? 0.041 0.071 0.051 0.046 0.061arrow_forwardDesigning an x -Chart Using the Process Standard DeviationThe Sunny Dale Bank monitors the time required to serve customers at the drive-through window because it is an important quality factor in competing with other banks in the city. After analyzing the data gathered in an extensive study of the window operation, bank management determined that the mean time to process a customer at the peak demand period is 5 minutes, with a standard deviation of 1.5 minutes. Management wants to monitor the mean time to process a customer by periodically using a sample size of six customers. Assume that the process variability is in statistical control. Design an x-chart that has a type I error of 5 percent. That is, set the control limits so that there is a 2.5 percent chance a sample result will fall below the LCL and a 2.5 percent chance that a sample result will fall above the UCL. After several weeks of sampling, two successive samples came in at 3.70 and 3.68 minutes, respectively. Is the…arrow_forwardA component part for a motorcycle is manufactured by an investment casting process. The air vent opening on this casting is an important functional parameter of the part. The results for five samples are given in the table. The values given have been coded using the last two digits of the dimension Sample Air vent opening diameter (in mm 1 58 61 54 60 2 61 55 58 62 3 66 60 59 55 4 53 57 58 64 5 65 63 79 61 Determine the central line and control limits for the range and mean charts, and discuss whether or not the process is in statistical control.arrow_forward
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