These control charts are used to monitor the variance in product/service. The productivity and quality is increased as the operators and managers will know when the process is getting out of control.
There are 2 types of control charts:
1, x bar r charts: These charts are used to measure the variance of product characteristic. . It is used when the product attributes are measureable. It is computed by analysing small random samples over a period of time.
2. p charts: These charts are used to see the attribute compliance. When the product attributes do not yield any measurement but only a ‘yes or no’ answer/conclusion, these charts are used. It graphs the proportion of sample items which are not in compliance with the specifications.