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Yellow Belt would be good for you. You can learn the basics of LEan and Six sigma in yellow belt and apply on the projects that you do.

Six Sigma is a set of tools and techniques to reduce variations and improve quality. Basically you need to identify a issue at hand and apply various tools and techniques to improve. therefore the answer to your question is YES, absolutely! I presume that you conduct web based trainings. So you must be facing various issues e.g. Marketing issues, tool issues, content issues. When you want to run an improvement program you choose an issue and execute a project to improve. e.g. lets take a Tool issue that you may be facing. Then you will use the DMAIC methodology to DEFINE the issue first, MEASURE what wrong (latency, clarity issues, bandwidth etc), ANALYSE the issue, define IMPROVEMENT plan of action (changing the tool, improving the bandwidth etc) and finally CONTROL what you have defined as a solution.
Please also remember that the solution could be at many levels. The levels are generally defined using some of the standard models such as CIMM models. So the solution can be a basic solution at a CIMM level 1 or an advanced level such as CIMM level 4 or Level 5. As you increase the levels, the more statistical you solutions need to get and the more you need to achieve to really call it a Level 4 or Level 5 project. Hope this helps. Let me know if you need more clarifications.

Anyone who wishes to improve the current state of working should do Lean Six Sigma. Lean Six Sigma is a set of tools and techniques which will help you to reduce variation and improve quality. For e.g. if you are in software, you would work on six sigma techniques to reduce defects, if you are in manufacturing you would work on reducing your scrap. there are 2 options for you. One is yellow belt and second is green belt. Start with a Yellow Belt first. Worry about the statistics part (which is part of Green belt) later.