Six Sigma has multiple levels for learning called Yellow Belt, Green Belt, Black Belt & Master Black Belt. Those who successfully undergone this training would be treated as Six Sigma Certified. The underlying idea of being 'Six Sigma Certified' is that if you can measure how many 'defects' you have in a process, you can systematically figure out a way to eliminate them and get as close to 'zero defects' as possible.

6sigmastudy is the global certification body for six sigma certifications. The quality of its study resources, the credibility of certifications, use of technology to create user-friendly processes, simplified partner registration, and the focus on interactive training methodologies distinguishes it in the world of six sigma certifications. 

Not really. However, it is recommended to go step-by-step. Learn the theory & apply it practically to gain additional insights on different tools & techniques before moving to the next level. We recommend the students start with Six Sigma Yellow Belt whereas the working professionals can start with Six Sigma Green Belt.

Green Belts are employees of an organization who have been trained on the Six Sigma improvement methodology and will lead a process improvement team as part of their full‐time job. Operates under the supervision of a Six Sigma Black Belt.

If the admittedly-biased Go Lean Six Sigma training program is to be believed, Six Sigma belts can significantly increase your salary. The average Black Belt makes $99,000 a year; the level one below that makes $83,000 – a full 19% increase.