1. A system for statistical process control, comprising: a storage device storing a plurality of SPC charts, specifying data collected from a system during testing; a controller categorizing the SPC charts to a plurality of groups based on characteristics thereof; and a detector determining whether the charts within one of the groups violate a preset rule, wherein the rule identifies an indicator variable of a chart within one of the groups as a detection target, and the indicator variable is derived from the latest data entry in the chart, a preset number of data entries or data entries collected within a preset time period.