Data - C Chart
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You must have at least one column containing the number of defects. Each row of a column should contain the number of defects for one subgroup.

Suppose you collect data on the number of scratches found per square meter of finished surface each day. You sample the same number of square meters each day. The number of defects is the number of scratches found on a given day. Your data might like the Scratches column below.

When an observation is missing, a gap exists in the chart for that observation.