The following example uses the Coating.jmp data table. The quality characteristic of interest is the Weight column. A subgroup sample of four is chosen. An X-chart and an R-chart for the process are shown in Figure 3.17.
1.
Select Help > Sample Data Library and open Quality Control/Coating.jmp.
2.
Select Analyze > Quality and Process > Control Chart > XBar.
3.
Select Weight and click Process.
4.
Select Sample and click Sample Label.
5.
Note: If an S chart is chosen with the X-chart, then the limits for the X-chart are based on the standard deviation. Otherwise, the limits for the X-chart are based on the range.
Figure 3.17 Variables Charts for Coating Data
Figure 3.18 Box Plots for Coating Data
The box plots in Figure 3.18 show that the sixth sample has a small range of high values.

Help created on 7/12/2018