Number Of Defects (c)#
The following table lists the properties of the Number of Defects (c) chart.
| Property | Description |
|---|---|
| Chart | Number of Defects (c) |
| Process observation types | Attributes |
| Process observations relationships | Independent |
| Sample Size | Constant |
| Distribution type | Poisson |
| Size of shift to detect | Large (≥ 1.5σ) |
| Number of Defects (Indicator 1) | \(c=number\;of\;defects\) |
| Number of Defects (Indicator 2) | Not applicable |
| Standard Deviation | \(s = \sqrt{\overline{c}}\) Where \(\overline{c}\) is the centerline |
| Number of Defects (Indicator 1) Centerline | \(\overline{c}=\frac{c_1+c_2+\cdots+c_k}{k}\) where c is the number of defects per sample |
| Number of Defects (Indicator 1) Control Limits | \(UCL=\overline{c}+3s\) \(LCL = max(\overline{c}-3s;0)\) |
| Indicator 2 Centerline | Not applicable |
| Indicator 2 Control Limits | Not applicable |
Table: Number of Defects chart properties