Control Chart
Control chart is a graph used to study how a process changes over time and here data are plotted in time order.
1. Control chart has central line (CL) for the average.
2. An upper line for the upper control limit (UCL).
3. A lower line for lower control limit(LCL).
Type of control chart
Variable control chart
These chart are applied to data that follow a continuous distribution variable data are measured on a continuous scale.
For example- Time, Distance, weight or temperature can be measured in fraction or Decimal.
Attribute control Chart- Attribute data are counted and cannot have fraction or decimal. Attribute arise while determining only presence of absence of some thing like success or failure, Accept or reject,correct or non-correct etc.
Control Chart for Variable
SPC Methods-Developing Control Charts
Control Charts (aka process or QC charts) show sample data plotted on a graph with CL, UCL, and LCL.
Control chart for variables are used to monitor characteristics that can be measured, e.g. length, weight, diameter, time
Control charts for attributes are used to monitor characteristics that have discrete values and can be counted, e.g. % defective, # of flaws in a shirt, etc.
