A clothing manufacturer employs quality inspectors to traack the manufacturing process. From each lot produced at the factory, the inspectors take a sample of clothes and count the number of clothes that are unacceptable.

This information is collected in clothing_defects.sav Use Control Charts to track the proportion of defective clothes with a p chart.

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

Graphs
Control...

Select p, np.

Select Cases are subgroups.

Click Define.

Select Number defective as the number noncomforming variable.

Select Lot number as the subgroup labeling variable.

Select Variable in the Sample Size group and select Number sampled as the variable containing the sample sizes.

Click Continue.

Click OK.

These selections produce a p chart.