To run a Control Charts analysis, from the menus choose:

Graphs
Control...

Click Define.

Select pH level as the process measurement variable.

Select Time of measurement as the subgroup definition variable.

Click Statistics.

Type 5.5 as the upper specification limit (USL).

Type 4.5 as the lower specification limit (LSL).

Type 5.0 as the target.

Select CP, CpU, CpL, K, CpM, and Z-out in the Process Capability Indices group.

Select PP, PpU, PpL, PpM, and Z-out in the Process Performance Indices group.

Select Actual % outside specification limits.

Click Continue.

Click OK in the X-Bar, R, s: Cases are Units dialog box.

These selections produce a Range chart, X-bar chart, and process statistics table.