Describes the cause and action for error messages.
Error Message(English)：
absolute percentage error excel
Average Percent Error Ape - surfacelearning.org
http://surfacelearning.org/mean-absolute-percentage-error
Computer Repairs in Kentucky
http://digitalhaunt.net/Kentucky/
Computer Repairs in Pennsylvania
http://digitalhaunt.net/Pennsylvania/
Computer Repairs in West Virginia - SceneAdvisor
http://www.sceneadvisor.com/West-Virginia/