Primary Control Limits Chart Type Lower Upper X bar 5660731 7763269 243 17 NCSS

Primary control limits chart type lower upper x bar

This preview shows page 17 - 21 out of 27 pages.

Primary Control Limits Chart Type Lower Upper X-bar 56.60731 77.63269 243-17 © NCSS, LLC. All Rights Reserved.
NCSS Statistical Software NCSS.com X-bar and s Charts s 0 15.3864 This report gives the lower and upper limits for each of the charts, corresponding to a specific subgroup size. X-bar Lower and Upper Primary Control Limits These limits are the primary control limits of the X-bar chart, as defined in the sub-section X-bar Chart Limits of the Control Chart Formulas section toward the beginning of this chapter. s Lower and Upper Primary Control Limits These limits are the primary control limits of the s chart, as defined in the sub-section s Chart Limits of the Control Chart Formulas section toward the beginning of this chapter. Since the lower limit for the s chart is less than 0, it has been reset to 0. Sigma Estimation Section Sigma Estimation Section for Subgroups 1 to 50 Estimation Estimated Estimated Type Value Sigma Ranges (R-bar) 18.14 7.798796 Standard Deviations (s-bar)* 7.365443 7.835698 Weighted Approach (s-bar) 7.902911 7.902911 * Indicates the estimation type used in this report. This report gives the estimation of the population standard deviation (sigma) based on three estimation techniques. The estimation technique used for the plots in this procedure is based on the ranges. Estimation Type The two formulas for estimating sigma based on the standard deviation are shown earlier in this chapter in the Control Chart Formulas section. The formulas for the Ranges method are shown in the X-bar and R Charts chapter. Estimated Value This column gives the R-bar and s-bar estimates based on the corresponding formulas. Estimated Sigma This column gives estimates of the population standard deviation (sigma) based on the corresponding estimation type. X-bar and s Charts 243-18 © NCSS, LLC. All Rights Reserved.
NCSS Statistical Software NCSS.com X-bar and s Charts The first plot shows the sample means, as well as the centerline and control limits for the process mean, based on the 50 subgroups. This process appears to be in control. The second plot shows the sample standard deviations for each subgroup, as well as the corresponding centerline and limits. The s chart seems to indicate the variation is also in control. Out-of-Control List Out-of-Control List for Subgroups 1 to 50 Subgroup Subgroup Mean s Label Reason 30 70.4 12.01249 30 s: 4 of 5 in zone B or beyond This report provides a list of the subgroups that failed one of the runs tests (including points outside the control limits). The report shows that subgroup 30 is the final point of 4 out of 5 points in Zone B. This run does not appear to indicate a clear shift in the process variation. 243-19 © NCSS, LLC. All Rights Reserved.
NCSS Statistical Software NCSS.com X-bar and s Charts Example 2 – X-bar and s Charts Analysis (Phase II) This section presents a continuation of the previous example. In this example the limits are based on the first 50 observations, but the means and ranges are monitored for an additional 100 subgroups. The data are given in the columns D1ext – D5ext of the QC dataset.

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture