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Statistical Quality Control Sample Assignment

Questions: - A manufacture produces gauges to measure oil pressure. As part of the company’s statistical process control, 25 gauges are randomly selected and tested for nonconformance. The results are shown here. Use these data to construct a c chart that displays the nonconformance per item.

Item    _____________Number of __________ ______Item __________________Number of
Number_________Non conformaces____________Number_____________Nonconformances
    1_____________            2_____________                    14_______________                2
    2_____________            0_____________                    15_______________                1
    3_____________            3_____________                    16_______________                4
    4_____________            1_____________                    17_______________                0
    5_____________            2_____________                    18_______________                2
    6_____________            5_____________                    19_______________                3
    7_____________            3_____________                    20_______________                2
    8_____________            2_____________                    21_______________                1
    9_____________            0_____________                    22_______________                3
    10____________            0_____________                    23_______________                2
    11____________            4_____________                    24_______________                0
    12____________            3_____________                    25_______________                3
    13____________            2
______________________________________________________________________


Solution: -
Determine the cnetreline, UCL, and LCL.

Centerline = c = 2 + 0 + 3 + … + 3 = 50 = 2.0
            _____________25____        25

UCL = c + 3√c = 2.0 + 3√2.0 = 2.0 +4.2 = 6.2
LCL = c – 3√c = 2.0 – 3√2.0 = 2.0 – 4.2 = - 2.2

 The lower control limit cannot be less than zero; thus, the LCL is 0.  The graph of the control chart, followed by the MINITAB c chart, is shown next. Not that none of the points are beyond the control limits and there is a healthy deviation of points both above and below the centerline. This chart indicates a process that is relatively in control, with an average of two nonconformances per item.

Other Sample Assignments in Statistics Homework Assignment :

Continious Distribution	Descrete Distributions
Descriptive Statistics	Nonparamatric Statistics
Probability	Sampling And Sampling Distribution
Statistical Inference Estimation For Single Popula	Simple Regression Analysis
Statistical Inference About 2 Population	Time Series Forcasting Index Number
Statistical Quality Control	Correlation
Index Number	Larger Sample Mean Proportions
Non Parametric Test	Probability Theory
Sampling Distribution	Simple and Multiple Linear Regression Analysis
Unvariate Analysis

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