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.

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

Graphs
  Control...

step  Select p, np.

step  Select Cases are subgroups.

step  Click Define.

step  Select Number defective as the number noncomforming variable.

step  Select Lot number as the subgroup labeling variable.

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

step  Click Continue.

step  Click OK.

These selections produce a p chart.