Concept explainers
a)
To determine: The control limits for the mean and range chart and the overall means
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 plot: The values of sample means and ranges in the chart.
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: Whether the process is in control
Introduction: Control charts used to determine whether the process is under control or not. Attributes and variables are the factors under the control charts.
d)
To determine: Why the process is not in control
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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Chapter 6 Solutions
EBK PRINCIPLES OF OPERATIONS MANAGEMENT
- Mgt-314 (Operations Management) MCQ:arrow_forwardsniparrow_forwardWebster Chemical Company produces mastics and caulking for the construction industry. The product is blended in large mixers and then pumped into tubes and capped. Management is concerned about whether the filling process for tubes of caulking is in statistical control. The process should be centered on 8 ounces per tube. Several samples of eight tubes were taken, each tube was weighed, and the weights in Table were obtained. Ounces of Caulking Per Tube Tube Number Sample 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7.98 8.33 7.89 8.24 7.87 8.13 8.34 8.22 7.77 8.18 8.13 8.14 8.02 8.08 7.91 7.83 7.92 8.11 7.94 8.51 8.04 8.05 7.99 8.13 8.44 8.41 8.00 7.90 8.10 8.14 7.68 8.28 7.89 8.16 7.81 8.12 7.81 8.09 7.93 7.97 8.14 8.13 8.11 8.16 8.09 8.07 7.88 8.14 a. Assume that only six samples are sufficient and develop the control charts for the mean and the range.b. Plot the observations on the control chart and comment on your findings.arrow_forward
- 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: 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_forwardMcDaniel Shipyards wants to develop control charts to assess the quality of its steel plate. They take ten sheets of 1" steel plate and compute the number of cosmetic flaws on each roll. Each sheet is 20' by 100'. Based on the following data, develop limits for the control chart, plot the control chart, and determine whether the process is in control. Sheet Number of flaws 1 1 2 1 3 2 4 0 5 1 6 5 7 0 8 2 9 0 10 2arrow_forwardIn process industry during a daily production run, a total of five (05) samples are collected with four (04) observations within each sample. The sample means (X-bar) are; 14.09, 13.94,16.86, 20.00, and 16.64 respectively. The corresponding ranges are; 9.90, 7.73, 4.41, 7.56, and 3.49 respectively. The lower and upper control limits of the x-bar chart are respectively O a. 11.44, 20.66 O b. 11.29, 20.65 C. None is correct Od. 11.47, 21.14 e. 11.47, 16.55arrow_forward
- Thirty-five samples of size 7 each were taken from afertilizer-bag-filling machine. The results were overall mean =57.75 lb; average range = 1.78 lb.a) Determine the upper and lower control limits of the x -chart,where s = 3.b) Determine the upper and lower control limits of the R -chart,where s = 3.arrow_forwardDESIGNING A CONTROL CHART EXAMPLE Fujiyama Electronics, Inc. has been having difficulties with circuit boards purchased from an outside supplier. Unacceptable variability occurs between two drilled holes that are supposed to be 5 cm apart on the circuit boards. Thirty samples of 4 boards each were taken from shipments from the supplier as shown in the data listed below. Construct x and R charts for the process using the following data. DATA Sample No Samples 1 4.92 4.26 4.94 4.29 2 4.65 5.54 5.00 5.42 3 5.77 5.26 4.76 4.79 4 6.25 4.88 5.66 4.44 5 5.27 5.41 6.02 4.91 6 5.22 5.38 5.08 4.65 7 5.47 4.68 4.56 4.70 8 5.71 4.54 4.17 4.87 9 5.24 5.58 4.72 5.41 10 4.42 5.18 4.79 4.73 11 5.14 4.26 4.71 5.48 12 4.92 5.78 5.50 5.05 13 5.79 3.83 4.30 4.78 14 4.92 4.80 4.75 5.59 15 5.68…arrow_forwardA shirt manufacturer buys cloth by the roll from a supplier. For setting up a control chart to manage the irregularities (e.g., loose threads and tears), the following data were collected from a sample provided by the supplier. Sample Irregularities 1 2 2 1 3 4 4 2 5 0 6 4 7 3 8 0 9 2 10 1 Total 19 Calculate the LCL and UCL for a c-chart with z=2 LCL= 0, UCL = 4.66 LCL= 0, UCL = 3.28 LCL= -0.86, UCL = 3.28 LCL= -0.86, UCL = 3.51 LCL= -0.86, UCL = 4.66arrow_forward
- Control charts for X-bar and S are maintained for the fill volume of protein shake drink. The specifications are 330 + 10 mL. After 40 samples of size n=7 are analyzed, we find that: 40 40 = 13,200 Si = 296 i=1 i=D1 Find the best estimate of the process standard deviation. 7.498 7.400 7.570 2.737 7.713 8.032arrow_forwardManagement 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_forward1. The accounts receivable department at Rick Wing Manufacturing has been having difficulty getting customers to pay the full amount of their bills. Many customers complain that the bills are not correct and do not reflect the materials that arrived at their receiving docks. The department has decided to implement SPC in its billing process. To set up control charts, 10 samples of 50 bills each were taken over a month's time and the items on the bills checked against the bill of lading sent by the company's shipping department to determine the number of bills that were not correct. The results were: Sample No. 1 2 3 4 5 6 7 8 9 10 No. of Incorrect Bills 6 5 11 4 0 5 3 4 7 2 a) The value of mean fraction defective (p) = .094(enter your response as a fraction between 0 and 1, rounded to four decimal places). The control limits to include 99.73% of the random variation in the billing…arrow_forward
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