X-Bar & S Charts

How Do I Create X-Bar & S Charts in Excel Using SigmaXL?

X-Bar & S Charts

1. Open the file Catapult Data Xbar Control Charts.xlsx. Each operator fires the ball 3 times. The target distance is 100 inches. The Upper Specification Limit (USL) is 108 inches. The Lower Specification Limit (LSL) is 92 inches.
2. Select B2:F22; here, we will only use the first 20 subgroups to determine the control limits.
3. Select SigmaXL > Control Charts > X-Bar & S.
4. Do not check Use Entire Data Table!

   

5. Click Next. Select Subgroups across Rows, select Shot 1, Shot 2, Shot 3, click Numeric Data Variables (Y) >>; select Operator, click Optional X-Axis Labels >>. Check Tests for Special Causes as shown:
6. Click OK. Resulting X-bar & S charts:
7. This is currently a stable catapult process. Subgroups 21 to 25 were added afterwards. To add the additional data to this chart, click SigmaXL Chart Tools > Add Data to this Control Chart as shown:

X-Bar & S Charts Stacked Column Format

1. Open Customer Data.xlsx, click on Sheet 1. Click SigmaXL > Control Charts > X-Bar & S. Ensure that entire data table is selected. If not, check Use Entire Data Table. Click Next.
2. Select Stacked Column Format, select Overall Satisfaction, click Numeric Data Variable (Y) >>; select Order Date, click Subgroup Column or Size >>; select Order Date, click Optional X-Axis Labels >>. Ensure that Calculate Limits is selected. Check Tests for Special Causes as shown:

   

   Note: Subgroups are always displayed in the same order as given in the rows. They are not sorted by Order Date.

3. Click OK. The resulting X-bar & S charts are shown:

   

   The moving limits are due to the varying subgroup sizes. This appears to be a stable process, but typically one would want a minimum of 20 subgroups when creating a control chart. This example is for demonstration purposes only.