There are three levels as shown below.

Level3 - Indicator - Passive warning devices that caution you to perform correctly. Devices that identify a problem after the process, but before exposure to the customer.

-Example: Standard Work documents, Inspections prior to the next operation

Level2 - Control - Active warning of the problem as it is occurring during the process.

-Example: Alarms, Lights, Control charts, Delete key are you sure prompt

Level1 - Guarantee - Problem prevented from ever occurring at its source cause

-Example: One way assemblies, Automatic calculations, computerized forms that prevent processing with missing data

No copying, but refer to examples before determining which one Mistake Proofing - Specify the mistake proofing Level(out of three levels from above and see examples) of the following with explanation:

1)Pause-and-serve coffee makers so the coffee stops brewing when the pot is removed.

2)Circuit breakers that trip when they are overloaded.

3)Three-prong outlets so we cannot make the mistake of wrong polarity.

4)Alarms in cars that warn that you left the keys in the ignition.