ConceptDraw Community

I am currently taking a project management class, but I am bit confused with all of the various charts (FMEA, Cause and Effect, Pareto, histograms, etc.) and which project phase (DMAIC) they are the most beneficial. Some of the charts seem to be SO similar! In doing further research, the purpose of each chart and phase seems to be very subjective. Can anyone provide some input on these issues from "real world experiences"?
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Thanks in advance!