Total Process Variation DCOVA Total Process Common Cause Special Cause X Variation Variation Variation Variation is often due to differences in: ■People ■Machines ■Materials ■Methods ■ Measurement Environment Statistics for Managers Using Microsoft ExcelStatistics for Managers Using Microsoft Excel Total Process Variation Total Process Variation Common Cause Variation Special Cause Variation = +  People  Machines  Materials  Methods  Measurement  Environment Variation is often due to differences in: DCOVA