Posts tagged Control Chart Construction

The following formulas are used to compute the Centerlines for Statistical Process Control (SPC) charts.

The following formulas are used to compute the Upper and Lower Control Limits for Statistical Process Control (SPC) charts. Values for A2, A3, B3, B4, D3, and D4 are all found in a table of Control Chart Constants.

Studying Six Sigma? Learn the X-MR control chart construction rules here. 1. The data must be continuous.

2. The sample size is 1 and cannot vary.

3. Collect the data in a consecutive manner. (In production order)

4. For the first chart on a process, collect at least 20–25 sample groups to ensure that an adequate measure of process variation has been taken.

5. Calculate the data points to be plotted on the chart.