Datum Plot 0.3.10

Control charts and design of experiments.

Control charts (Analyze › Quality › Control Chart)

• Individuals and moving range for one value per row, X̄ and R or X̄ and S for subgroups (each row a subgroup in its sub-columns), and the p chart for defectives out of the number inspected.
• 3σ limits, points beyond them and runs of 8 on one side of the centre line are flagged; give the specification limits for Cp and Cpk.

Design of experiments

• New Design makes a two-level factorial design as a table: 2 to 7 factors, full factorial or half fraction, replicates and centre points, the factors coded −1/+1 and the runs in a random order (row titles). Type each result in the Response column.
• Factorial Analysis gives each factor's and interaction's effect with its test (Lenth's method when there are no replicates), a Pareto chart of the effects and the main-effect plot.

Checked: the control limits equal the textbook constants (A2, D4, A3, B4, 2.66, 3.267) and the binomial limits of the p chart; known effects are recovered from a simulated design; designs are balanced and orthogonal.