Computes points and limits for an np Chart - a control chart for number non-conforming. A range of indices for samples to be used and specific indices to ignore in the control calculation can also be specified. The actual number of samples used to calculate the control limits is supplied. FORMULAS: pbar = · r / (n x r array length) UCLnp = n x pbar + stderr mult x sqrt(n x pbar x (1-pbar)) CLnp = n x pbar LCLnp = n x pbar - stderr mult x sqrt(n x pbar x (1-pbar)) standard error = sqrt(n x pbar x (1-pbar))


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Inputs/Outputs

  • cnclst.png chart limit src —

    chart limit src specifies whether or not to use standard values for the chart limit calculations. If unwired this defaults to the most common case where the chart limits are calculated from the data in the input array. You do not have to wire this cluster unless you want the chart limits to be calculated from standard values. When using standard values, the center line for the control chart, np-bar, is set to n*p0.

  • cenum.png source —

    chart limit src specifies whether or not to use standard values for the chart limit calculations. If unwired this defaults to the most common case where the chart limits are calculated from the data in the input array. You do not have to wire this cluster unless you want the chart limits to be calculated from standard values. When using standard values, the center line for the control chart, np-bar, is set to n*p0.

  • cdbl.png std p0 —

    chart limit src specifies whether or not to use standard values for the chart limit calculations. If unwired this defaults to the most common case where the chart limits are calculated from the data in the input array. You do not have to wire this cluster unless you want the chart limits to be calculated from standard values. When using standard values, the center line for the control chart, np-bar, is set to n*p0.

  • c1ddbl.png r:# units non-conforming/sample —

  • cu32.png n: sample size —

    (U32) - Size of the unit sample.

  • cdbl.png std error multiplier (3) —

    (DBL, default = 3.0). Ordinarily you would leave this unwired and the control chart limits are computed as +/- 3.0 standard errors.

  • cnclst.png index spec —

    (Optional) cluster of: start index (I32) - index of the first sample to include in the control limit calculation. Default is 0 or index of the first sample in samples X array. end index (I32) - index of the last sample to include in the control limit calculation. Default is 0 which selects the last sample in samples X array. If this cluster is unwired, all samples in samples X input array are included in the control limit calculation.

  • ci32.png start index —

    (I32) - index of the first sample to include in the control limit calculation. Default is 0 or index of the first sample in samples X array.

  • ci32.png end index —

    (I32) - index of the last sample to include in the control limit calculation. Default is 0 which selects the last sample in samples X array.

  • c1di32.png indices to ignore —

    indices to ignore is the indices of samples to exclude from the control limit calculation. Excluding samples is useful for eliminating out of control points from the control limit calculation. By default, this is an empty array.

  • ii32.png # samples in calc —

    (I32) - the number of samples used in the control limits calculation.

  • i1ddbl.png r:# units non-conforming/sample unit —

    r:# units non-conforming/sample unit is the number of units non-conforming per sample inspected.

  • inclst.png np chart limits —

    cluster of: UCLnp (DBL) - the upper control limit. If std error multiplier is 3, this will be np-bar + 3 standard errors. CLnp (DBL) - the center line for the np control chart, np-bar. np-bar is the estimated number non-conforming for the process. LCLnp (DBL) - the lower control limit. If std error multiplier is 3, this will be np-bar - 3 standard errors. standard error (DBL) - the standard error associated with np-bar.

  • idbl.png UCLr —

    (DBL) - the upper control limit. If std error multiplier is 3, this will be np-bar + 3 standard errors.

  • idbl.png np-bar —

    (DBL) - the center line for the np control chart, np-bar. np-bar is the estimated number non-conforming for the process.

  • idbl.png LCLr —

    (DBL) - the lower control limit. If std error multiplier is 3, this will be np-bar - 3 standard errors.

  • idbl.png standard error —

    (DBL) - the standard error associated with np-bar.

    • np Chart Details

    The control limit calculations are as follows:If standard values are used for the control limit calculations, then np-bar is set to std n*p0, otherwise, np-bar is calculated from the input samples as specified by the index spec and indices to ignore inputs., if calculated from input data, otherwise